01. [ELEX]

. An alloy of 22 percent iron and 78 per cent nickel. A. Permalloy B. Alnico C. Constantan D. Manganin

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. Electric field intensity is measured in A. volts/meter B. Newton/meter C. Newton-meter D. Amperes/meter

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. Lenz's law is the consequence of the law of conservation of A. Energy B. Charge C. Field lines D. Momentum

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.A law stating that the magnetic susceptibilities of most paramagnetic substances are inversely proportional to their absolute temperatures. A. Curie's Law B. Child's Law C. CR Law D. Curie-Weiss Law

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.Flux density is measured in A. Tesia B. Weber C. Ampere- turn D. Maxwell

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.If the magnetic material is located within a coil through which alternating current (60 Hz frequency) flows, then hysteresis loops will be formed every second. A. 60 B. 120 C. 30 D. 180

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.One farad equals A. 1 coulomb/volt B. 1 newton/coulomb C. 1 newton-meter D. 1 volt/second/ampere

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.One of the common application of an air- cored choke. A. Radio frequency B. Audio frequency C. Power supply D. Power transformer

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.The permeability of permalloy is A. Very much greater than permeability of air B. Slightly greater than permeability of air C. Slightly less than permeability of air D. Equal to the permeability of air

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301. What composes all matter whether a liquid, solid, or gas? A. Atoms B. Electrons C. Protons D. Neutrons

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303. What is the smallest element of a matter? A. atom B. molecule C. crystal D. wafer

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304. To determine whether a material can support the flow of electricity or not, we need to examine its A. atomic structure B. physical state C. molecular structure D. chemical composition

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307. Known as the simplest type of atom. A. Hydrogen B. Oxygen C. Helium D. Nitrogen

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311. The nucleus of an atom is normally A. neutral B. positively charged C. negatively charged D. either positively or negatively charged

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312. What particles that revolve around the positive nucleus? A. electrons B. protons C. neutrons D. electrons & protons

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313. In electricity, positive electric charge refers to ____________. A. protons B. neutrons C. electrons D. atoms

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314. What is the charge of an electron? A. 1.6022 x 10^-19 C B. 9.1096 x 10^-19 C C. 1.6022 x 10^-31 C D. 9.1096 x 10^-31 C

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316. Protons are about _________ heavier than electrons. A. 1,800 times B. less than thrice C. less D. twice

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318. The maximum number of electrons (Ne) that can occupy a given shell (n) is determined by the formula A. Ne = 2n^2 B. Ne = n^2 C. Ne = 2^n D. Ne = 2n

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320. Maximum number of orbiting electrons at the first or K shell A. 2 B. 4 C. 6 D. 8

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329. Electrons at the conduction band are called A. free electrons B. valence electrons C. deep state electrons D. shallow state electrons

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332. Which material has more free electrons? A. Conductor B. insulators C. mica D. dielectric

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333. Which material has the least number of valence electrons? A. conductor B. semiconductor C. insulator D. semi-insulator

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335. A good conductor has how many valence electrons? A. 1 B. 2 C. 4 D. 8

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341. From the combined energy-gap diagram, which material has the widest gap between valence band and the conduction band? A. conductor B. semiconductor C. super conductor D. insulator < View Answer: 342. From the combined energy-gap diagram, which material has the smallest energy gap between valence band and the conduction band? A. conductor B. semiconductor C. super conductor D. insulator

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344. The difference in energy between the valence and conduction bands of a semiconductor is called A. band gap B. extrinsict photoeffect C. conductivity D. energy density

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345. The energy gap between the valence band and conduction band of a conductor is in the order of A. zero electron volt (0 eV) B. one electron volt (1 eV) C. five electron volt (5 eV) D. ten electron volt (10 eV)

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351. Ion is __________. A. an atom with unbalanced charges B. free electron C. proton D. nucleus without protons

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354. An electrical insulator can be made a conductor by A. ionizing B. electroplating C. oxidizing D. metalization

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361. A structure for solids in which the position of atoms are predetermined A. Crystalline B. Polycrystalline C. Lattice D. Non-Crystalline

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365. Ideally, all atoms have the same number of positively charged protons and negatively charged electrons, and is therefore considered as A. electrically neutral B. physically stable C. magnetically aligned D. technically rigid

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366. When the charge of an atom becomes unbalanced, the atom is said to carry A. Electric charge B. Magnetic charge C. Electromagnetic charge D. Electrical current

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367. A charged atom is also known as A. ion B. anion C. cation D. domain

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368. An atom or group of atoms that carries a net electric charge is called A. ion B. anion C. cation D. domain

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377. One Coulomb of charge has how many electrons? A. 6.24 x 10^18 electrons B. 6.24 x 10^19 electrons C. 62.4 x 10^18 electrons D. 62.4 x 10^19 electrons

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378. Coulomb is the SI unit of charge, how about in cgs? A. Statcoulomb B. electron volt C. electron unit D. static unit

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379. Statcoulomb is also known as A. electrostatic unit (esu) B. electron volt C. electron unit D. static unit

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380. An isolated body under normal condition is always A. neutral B. positively charged C. negatively charged D. ionized

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383. The rate at which electrons pass a given point in the circuit gives the magnitude of A. electron current B. magnetic current C. drift current D. diffusion current

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384. The unit of current. A. Ampere B. Ampere/sec. C. Ampere-sec. D. Ampere-hr.

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385. The unit Ampere is equivalent to A. one Coulomb/second B. one Coulomb/min C. one Joule/sec D. one Joule/min

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388. The bigger the diameter of a wire, A. more current can pass B. less current can pass C. more heat is generated when current flow D. the higher is the electrical resistance

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391. The longer the wire the ________ is the resistance A. higher B. lesser C. harder D. smaller

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393. The amount of resistance that a wire has with regards to the flow of electric current A. is less for a conductor than for an insulator B. is less for an insulator than for a semiconductor C. is less for a semiconductor than for a conductor D. is high for a semiconductor than for an insulator

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4.If the number of valence electrons of an atom is exactly 4, then the substance is called A. a semiconductor B. a conductor C. an insulator D. a cryogenic conductor

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401. Where does practically all of the RF current flow in a conductor? A. along the surface B. in the center of the conductor C. in the electromagnetic field in the conductor center D. in the magnetic field around the conductor

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403. Why is the resistance of a conductor different for RF current than for DC? A. Because of skin effect B. Because conductors are non-linear devices C. Because the insulation conducts current at radio frequency D. Because of the Heisenberg effect

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414. The space outside or surrounding an electric charge where it has a force of attraction or repulsion. A. Electric field B. Magnetic field C. Electromagnetic field D. Electric flux

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421. Find the dielectric constant of air. A. approximately 1 B. approximately 0 C. approximately 2 D. approximately 4

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422. Electric field intensity is measured in terms of A. Volts/meter B. Newtons/meter C. Watts/meter D. Amperes/meter

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424. Electric flux is a/an ________ quantity. A. scalar B. vector C. absolute D. relative

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430. The absolute permittivity of air or free space. A. 1/36π x 10^-9 F/m B. 36π x 10^-9 F/m C. 1/36π x 10^-19 F/m D. 36π x 10^-19 F/m

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435. Relative permittivity is also known as A. dielectric constant B. dielectric strength C. isolation strength D. permeability

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440. The force between two electrically charged body is A. directly proportional to the charge B. inversely proportional to the charge C. not affected by the charge D. universally constant

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447. Determine the magnitude of the electric field inside a sphere that encloses a net charge of 2 μC. A. 0 (zero) B. 9 x 10^7 N/C C. 1.8 x 10^8 N/C D. infinite

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450. A charged body in free space produces 10-V potential at a distance 25 cm away. What will be the potential at 50 cm away? A. 5.0 Volts B. 7.5 Volts C. 10.0 Volts D. 15.0 Volts

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453. A substance that attracts pieces iron is known as A. magnet B. conductor C. ferrite D. superconductor

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458. Is believed to be the pole where the magnetic lines of force are originating. A. North Pole B. South Pole C. Unit Pole D. Universal Pole

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462. A force which causes a substance to become a magnet. A. magnetizing force B. magnetomotive C. creative force D. electromagnetic force

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464. Is the property of magnetic materials, which retain magnetism after the withdrawal of magnetizing force. A. retentivity B. permeability C. reluctivity D. susceptability

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466. Which of the materials below that can be easily magnetized? A. soft magnetic materials B. hard magnetic materials C. low conductive materials D. high conductive materials

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467. Materials that can be easily magnetized in both directions A. soft magnetic materials B. hard magnetic materials C. diamagnetic D. paramagnetic

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470. The permeability of free space. A. 4π x 10^-7 H/m B. 12.56 x 10^-7 F/m C. 8.854 x 10^-7 H/m D. 8.854 x 10^-12 F/m

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473. Materials with permeability slightly less than that of free space. A. diamagnetic B. paramagnetic C. ferromagnetic D. antimagnetic

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476. What is the relative permeability of paramagnetic substance? A. slightly greater than 1 B. very much greater than 1 C. slightly less than 1 D. very much smaller than 1

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480. Hydrogen is an example of a _________ material. A. diamagnetic B. ferromagnetic C. paramagnetic D. magnetic

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482. The space outside a magnet where its poles has a force of attraction or repulsion on another magnetic pole. A. magnetic field B. magnetic flux C. magnetic flux density D. magnetic lines of force

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489. What is the unit of magnetic flux in SI system? A. Weber B. Maxwell C. Tesla D. Gauss

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491. A magnetic flux of 25,000 Maxwell in an area of 5 sq. cm. results in flux density of A. 5,000 Gauss (G) B. 125,000 G C. 5,000 Tesla (T) D. 125,000 T

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499. Unit of permeability A. Henry/meter (H/m) B. Farad/meter (F/m) C. Henry-meter (H-m) D. Farad-meter (F-m)

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5.What is the cgs unit of magnetomotive force? A. Gilbert B. Ampere- turn C. Maxwell D. Weber

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501. Magnetic intensity is A. a vector quantity B. a scalar quantity C. an imaginary quantity D. either a vector or scalar

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504. One Weber is equivalent to A. 10^8 Maxwells B. 10^6 Maxwells C. 10^4 Maxwells D. 10^2 Maxwells

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515. Permeance is analogous to A. conductance B. resistance C. impedance D. elastance

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519. The Oersted (Oe) is the same as A. 1 Gb/cm B. 1 Gb/m C. 10 Gb/cm D. 10 Gb/cm

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527. The current needed for a coil of 200 turns to provide a 400 ampere turn magnetizing force is A. 2 A B. 4 A C. 6 A D. 8 A

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534. The amount of magnetic field needed to remove residual magnetism from a transformer core during each half cycle is called the A. coercive force B. residual field C. hysteresis field D. demagnetizing force

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535. If a wire coil has 100 turns and carries 1.3 A of current, calculate the magnetomotive force in Gilbert. A. 163.3 B. 16.33 C. 1.633 D. 0.1633

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539. What is a magnetic field? A. A force set up when current flows through a conductor. B. A force set up when a charged body is at static. C. The space between two electrically charged particles. D. The space around a conductor.

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540. Which of the following determines the strength of a magnetic field around a conductor? A. amount of current B. diameter of the conductor C. length of the conductor D. amount of voltage

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542. In what direction is the magnetic field about a conductor when current is flowing? A. In a direction determined by the left-hand rule. B. Always in a clock wise direction. C. Always in a counter clockwise direction. D. In a direction determined by the right-hand screw rule.

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543. If the electrical current carried by each of the two long parallel wire is doubled, and their separation is also doubled, the force between them A. also doubles B. increases by a factor of four C. decreases by a factor of four D. decreases by a factor of two

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544. Reversing the flow of current in a circuit A. reverses the magnetic polarity B. increase the magnetic field intensity C. decreases the magnetic intensity D. enhances hysteresis

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546. What law that describes the force of attraction or repulsion between two magnetic poles is directly proportional to their strengths? A. Coulomb's first law B. Coulomb's second law C. Ampere's law D. Gauss' law

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548. The physical motion resulting from the forces of magnetic fields. A. motor action B. linear motion C. rectilinear motion D. generator action

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6. 0ne coulomb of charge consists of electrons. A. 6 4 X 10"16 B. 62.4 x 10A16 C. 6.24 x 10A16 D. 0.624 x 10A16

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7.Mmf in a magnetic circuit corresponds to in an electric circuit A. Emf B. Voltage drop C. Electric Field Intensity D. Potential gradient

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A commercial alloy of aluminum nickel, and iron with cobalt, copper and titanium added to produce about 12 grades. A. Alnico B. Brass C. Aluminum D. Constantan

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A current if flowing east along a power line. If the earth's field is neglected, the direction of the magnetic field below it is A. North B. South C. East D. West

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A good conductor has how many valence electrons? A. 1 B. 4 C. 2 D. 8

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A magnetic circuit carries a flux cpi in the iron part and a flux cpg in the air gap. What is the leakage coefficient? A. 'PiI 'Pg B. cpi X cpg C. cpg /cpi D. cpi + cpg

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A magnetic material losses its ferromagnetic properties at a point called A. Curie temperature B. Inferred absolute temperature C. Room temperature D. Absolute temperature

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A magnetic pole produces 5000 field lines. How much is the flux in webers? A. 50 X 10"-6 B. 5 x 10A-6 C. 500 x 10A6 D. 500 x 10A-5

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A magnetizing force of 1000 AT/m will produce a flux density of in air. A. 1.257 mWb/m"2 B. 0.63 Wb/m"2 C. 1.257 Wb/m"2 D. 0.63 mWb/m"2

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A negative ion results when an atom gains an additional A. Electron B. Proton C. Neutron D. Atom

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A positively charged body has A. deficit of electrons B. excess of neutrons C. excess of electrons D. deficit of protons

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All magnetic field originates from A. moving electric charge B. Iron atoms C. Magnetic domain D. Permanent magnet

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An electron- volt (eV) is a unit of A. Energy B. Potential difference C. Charge D. Momentum

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Calculate the permeability (in T/A. t/m) of a magnetic material that has a relative permeability of 300 A. 3.78 x 10"-4 B. 3.78 x 10'-5 C. 3.78 x 10'-3 D. 3.78 x 10'-6

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Defined as the ratio of the volume occupied by the atoms or ions in a unit cell divided by the volume of the unit cell and is used to measure the compactness of a crystal. A. Atomic packing factor (APF) B. Ionic Packing Ratio (IPR) C. Atomic compacting factor (ACF) D. Ionic compacting ratio (ICR)

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Electric potential is a quantity. A. scalar B. phasor C. vector D. variable

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Electromotive force in a circuit A. causes free electrons to flow B. increases the circuit resistance C. maintains circuit resistance D. is needed to make the circuit complete

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Electron is a Greek word for A. amber B. Fire C. Stone D. Heat

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Electronic current in a wire is the flow of electrons. A.free B. valence C. bound D. loose

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Germanium atom has protons and electrons. A. 32, 32 B. 32, 42 C. 42, 32 D. 34, 34

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Hipernik is an alloy containing iron and nickel. A. 40% ; 60% B. 60% ; 40% C. 50% ; 50% D. 70% ; 30%

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How many electrons are needed in the valence orbit to give a material's stability? A. 8 B. 4 C. 6 D. 5

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How much is the flux in Weber in the above problem? A. 2 x 10"-5 B. 2 x 10'- 3 C. 2 x 10' D. 2 x 10'3

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If a magnetic flux cuts across 200 turns at a rate of 2Wb/s, the induced voltage according to Faraday's law is about A. 400 V B. 100 V C. 200 V D. 600 V

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If the number of valence electrons of an atom is less than 4, the substance is called A. a conductor B. a semiconductor C. an insulator D. a superconductor

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If the number of valence electrons of an atom is less than 4, then the substance is probably A. a metal B. an insulator C. a non-metal D. a semiconductor

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If the value of a25 of a conductor is 1/230 per o C, then the value of a0 is A. 1/180 per oC B. 1/150 per oC C. 1/280 per oC D. 1/230 per oC

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In electro-mechanical conversion devices like generators and motors the reason whya small air gap is left between the rotor and stator is to A. permit mechanical clearance B. increase flux density in air gap C. decrease the reluctance of magnetic path D. complete the magnetic path

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Materials whose permeabilities are slightly greater than that of free space A. Paramagnetic B. Non- magnetic C. Ferromagnetic D. Diamagnetic

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One oersted (Oe) is equivalent to Gb/cm. A. 1 B. 10 C. 100 D. 1000

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One of the solid structures in which the position of the atoms or ions are predetermined A. Crystalline solid B. Amorphous solid C. Polycrystalline solid D. Poly- amorphous solid

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Permeability means A. The conductivity of the material for magnetic lines of force B. The magnetization test in the material after exciting field has been removed C. The strength of an electromagnet D. The strength of the permanent magnet

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Permeance is analogous to A. Conductance B. Reluctance C. Admittance D. Resistance

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Permeance of a magnetic circuit is the cross-sectional area of the circuit. A. directly proportional to B. inversely proportional to C. dependent of D. independent of

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Refers to the magnetic lines A. Flux B. Hysteresis C. Current D. Magnetomotive force

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Refers to the non- metallic materials that have the ferromagnetic properties of iron. A. Ferrites B. Ferromagnetic C. Diamagnetic D. Paramagnetic

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Steel is hard to magnetize because of its A. Low permeability B. High permeability C. High density D. High retentivity

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Temporary magnets are commonly employed in A. electric instruments B. motors C. moving coils loudspeakers D. magnetos

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The air space between poles of magnets A. Air gap B. Free space C. Vacuum D. Atmosphere

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The conduction of electricity across the surface of a dielectric is called A. creepage B. skin effect C. surface effect D. crosstalk

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The dielectric constant of most materials lies between A. 1 and 10 B. 10 and 20 C. 20 and 50 D. 50 and 100

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The emf induced in a coil due to the changing current of another neighboring coil is called A. Mutually induced emf B. Self induced emf C. Statically induced emf D. Dynamically induced emf

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The emf produced in a wire by its motion across a magnetic field does not depend upon the A. Diameter of the wire B. Length of the wire C. Orientation of the wire D. Flux density of the field

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The force acting on a pole of 5 Wb is 25 N. What is the intensity of the magnetic field? A. 5 N B. 25 N/Wb C. 125 N/Wb D. 0.2 N/Wb

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The force acting on a unit n- pole placed at that point is called A. Magnetic field intensity B. Electric field intensity C. Electromagnetic field intensity D. Intensity magnetization

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The hot resistance of an incandescent lamp is about its cold resistance. A. 10 times B. 100 times C. 5 times D. 50 times

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The induced emf in a wire loop that is moved parallel to a uniform magnetic field is A. Zero B. Dependent on the area of the loop C. Dependent on the shape of the loop D. Dependent on the magnitude of the field

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The magnetic field of a magnetized iron bar when strongly heated A. Becomes weaker B. Becomes stronger C. Reverses in direction D. is unchanged

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The magnetic flux through a coil changes. This results to the induced emf acting in a direction as to A. Oppose the change B. Aid the change C. Either oppose or aid the change D. Neither oppose nor aid the change

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The magnetic potential in a magnetic circuit can be measured in terms of A. Mmf B. Emf C. Farad D. Coulomb

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The net electrical charge in an isolated system remains constant. This is known as A. Law of conservation of charge B. Coulomb's first law C. Coulomb's second law D. Law of conservation of energy

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The phenomenon by which a subtracts pieces of iron A. Magnetism B. Electromagnetism C. Naturalism D. Materialism

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The phenomenon that when an electric current passes through an anisotropic crystal, there is an absorption or liberation of heat due to the non-uniformity in current distribution. A. Bridgman effect B. Corona effect C. Dember effect D. Destriau effect

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The physical motion resulting from the forces of magnetic fields is called A. Motor action B. Rotation C. Repulsion D. Torque action

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The point in a magnet where the intensity of magnetic lines of force is maximum A. Magnetic pole B. South pole C. North pole D. Unit pole

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The potential at a point due to a charge is 15 V. If the distance is increased three times, the potential at the point will be A. 5 V B. 18 V C. 45 V D. 15 V

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The process by which an emf and hence current is generated or induced in a conductor when there is a change in the magnetic flux linking the conductor is called A.Electromagnetic induction B. Mutual induction C. Faraday's law D. Electromagnetic interference

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The property of magnetic materials of retaining magnetism after withdrawal of the magnetizing force is known as A. Retentivity B. Reluctivity C. Resistivity D. Conductivity

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The quantity 10'8 maxwells is equivalent to one A. Weber B. Gauss C. Gilbert D. Tesla

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The ratio of the permeability of material to the permiabiity of air or vacuum. A. Relative permeability B. Relative permittivity C. Relative conductivity D. Relative reluctivity

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The space outside the magnet where its pole have a force of attraction or repulsion on a magnetic pole is called A. Magnetic field B. Electric field C. Electromagnetic field D. Free Space Field

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The temperature coefficient of resistance of conductors is A. positive B. zero C. negative D. infinite

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The tiniest element of matter A. Atom B. Proton C. Electron D. Neutron

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The total number of magnetic lines of force in a magnetic field is called A. Magnetic flux B. Magnetic flux density C. Magnetic flux intensity D. Magnetic potential

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Theory of ferromagnetic phenomena which assumes each atom is a permanent magnet which can turn freely about its center under the influence of applied field and other magnets. A. Ewing's theory of ferromagnetism B. Oersted's ferromagnetism theory C. Maxwell's magnetic theory D. Ampere's circuital law

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This paper does not exhibit electricity because it contains the same number of A. protons and electrons B. neutrons and electrons C. neutrons and positrons D. atoms

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Three charges of +5 C, -6 C and +9 C are placed inside a sphere. What is the total flux passing through the surface of sphere? A. 8 C B. 14 C C. 20 C D. -6 C

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Two similar poles, each 1Wb, placed 1 m apart in air will experience a repulsive force of A. 63000 N B. 63 x 1 -3 N C. 8 x 1 12 N D. 796 kN

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What bond is formed when one or more electrons in the outermost energy orbit of an atom are transferred to another? A. Ionic B. Covalent C. Metallic D. Van der Waals

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What determines the atomic number of an element? A. The number of protons B. The number of electrons C. The number of neutrons D. The number of neutrons and protons

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What is the SI unit of conductance? A. Siemens B. Mhos C. Ohms D. 1/Ohms

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What is the SI unit of specific resistance or resistivity? A. Ohm-circular mil per inch B. Ohm-circular mil per foot C. Ohm-m D. Ohm-cm

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What is the diameter of an atom? A. About 10"-10 m B. About 10"-10 cm C. About 10"-10 mm D. About 10"-10 µm

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What is the main advantage of temporary magnets? A. The magnetic flux can be changed. B. Hysteresis can be decreased. C. Magnetic materials can be used. D. Abundance of ferromagnetic material that can be temporarily magnetized

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What is the measure of the density and sign of the electric charge at a point relative to that at sometime? A. Electric potential B. Electric charge C. Electric current D. Electric intensity

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What is the other name for dielectric strength? A. Breakdown voltage B. Electric intensity C. Potential gradient D. Dielectric constant

A

What is the reluctance of a magnetic path having a length of 2x 10'-3m and crosssectional area of 2.5 x 10'-3 m'2? A. 6366 A.t/Wb B. 6000 A.t/Wb C. 8x10'-3 A.t/Wb D. 0.8 A.t/Wb

A

When a conductor is stationary and the magnetic field is moving or changing the emf induced is called A. Statically induced emf B. Mutually induced emf C. Self induced emf D. Dynamically induced emf

A

When the relative permeability of a material is slightly less than 1, it is called material. A. diamagnetic B. ferromagnetic C. paramagnetic D. non-magnetic

A

Which of the following electric quantities is vector in character? A. Field B. Charge C. Energy D. Potential Difference

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Which of the following has the least number of valence electrons? A. Conductor B. Semiconductor C. Insulator D. Semi- insulator

A

Which of the following magnetic materials can be easily magnetized in both direction? A. Soft magnetic materials B. Hard magnetic materials C. High hysteresis loss materials D. Low hysteresis loss materials

A

Which of the following materials has the highest dielectric strength? A. Glass B. Oiled paper C. Mica D. Air

A

Who demonstrated the theory of electromagnetic induction in 1831? A. Michael Faraday B. Andre Ampere C. James Clerk Maxwell D. Charles Coulomb

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Who discovered superconductivity in 1911? A. Kamerlingh Onnes B. Alex Muller C. Geory Bednorz D. Charles Coulomb

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Who discovered that a current-carrying conductor would move when placed in a magnetic field? A. Michael Faraday B. Andre Ampere C. Hans Christian Oersted D. Gustav Robert Kirchhoff

A

Who discovered the most important electrical effects which is the magnetic effect? A. Hans Christian Oersted B. Sir Charles Wheatstone C. Georg Ohm D. James Clerk Maxwell

A

. Hydrogen is an example of a material. A. Paramagneti c B. Diamagnetic C. Ferromagnetic D. Non- magnetic

B

. If the value of a0 a conductor is 1/234 per o C, then the value of a18 is A. 1/218 per oC B. 1/252 per oC C. 1/272 per oC D. 1/273 per oC

B

. Referred to as the specific reluctance of a material A. Resistivity B. Reluctivity C. Conductivity D. Permeability

B

.A one cubic cm of copper has how many free electrons at room temperature? A. 80 x 10A18 B. X 10" C. 20 x 10A10 D. 50 x 10A20

B

.Hysteresis loss can be reduced by one of the following. A. Increasing mmf of the circuit B. Using material narrow hysteresisloop C. Using ferromagnetic core D. Laminating the magnetic circuit

B

.The temperature coefficient of resistance of a conductor with an increase in temperature. A. increases B. decreases C. remains the same D. becomes negative

B

214. The reciprocal of reluctance A. conductance B. permeance C. elastance D. capacitance

B

308. Approximate diameter of a Hydrogen atom A. 1.1 x 10^-10 µµm B. 1.1 x 10^-10 µm C. 1.1 x 10^-10 mm D. 1.1 x 10^-10 m

B

315. The mass of a proton is approximately A. 1.6726 x 10^-19 Kg B. 1.6726 x 10^-27 Kg C. 1.6022 x 10^-19 Kg D. 1.6022 x 10^-27 Kg

B

331. Electrons at the outermost shell are called A. free electrons B. valence electrons C. deep state electrons D. shallow state electrons

B

336. Materials that might have eight valence electrons A. conductor B. insulator C. semiconductor D. semi-insulator

B

339. Determine which statement is true? A. The current carriers in conductors are protons. B. The current carriers in conductors are valence electrons. C. Valence and inner electrons are the carriers in conductors. D. Valence electrons are not the ones that become free electrons.

B

349. A factor that does not affect the resistance of the material. A. atomic structure B. mass C. length D. cross-sectional area

B

355. Refers to the lowest voltage across any insulator that can cause current flow. A. conduction voltage B. breakdown voltage C. voltage flow D. voltage drop

B

357. When all atoms of a molecule are the same, the substance is called A. a crystal B. an element C. a compound D. an ion

B

359. Isotope means, the same element but with different number of A. electrons B. neutrons C. protons D. atoms

B

372. What do you call a negatively charged ion? A. electron B. anion C. cation D. domain

B

376. Gases with charged particles. A. inert B. plasma C. conductive D. reactive

B

382. The net movement of charged particles in one direction or another. A. flow B. current C. drift current D. diffusion current

B

390. The greater the diameter of a wire, the _______ is the resistance. A. greater B. lesser C. harder D. bigger

B

394. The area of a conductor whose diameter is 0.001 inch is equal to A. one angstrom B. one circular mil C. one micron D. one steradian

B

406. Electron volt (eV) is a unit of A. power B. energy C. magnetic field D. magnetic force

B

411. Test charge has a charge of A. 0 Coulomb B. +1 Coulomb C. -1 Coulomb D. Infinity

B

418. What do you call the total number of electric lines of force in an electric field? A. Electric field B. Electric flux C. Electric flux density D. Electric lines of force

B

423. Electric field intensity is A. a scalar quantity B. a vector quantity C. an absolute value D. a relative value

B

425. Electric flux density is a/an ________ quantity. A. scalar B. vector C. absolute D. relative

B

426. Three charges of +5 C, -6 C, and +7 C are inside a sphere, what is the total electric flux passing through the surface of the sphere? A. 5 Coulombs B. 6 Coulombs C. 7 Coulombs D. 8 Coulombs

B

431. The relative permittivity of air. A. 0 B. 1 C. 1/36π x 10^-9 F/m D. 8.854 x 10^-12 F/m

B

432. Calculate the permittivity of a material with relative permittivity of 5. A. 8.854 x 10^-11 F/m B. 4.42 x 10^-11 F/m C. 1/36π x 10^-9 F/m D. 8.854 x 10^-12 F/m

B

434. How does permittivity affect electric field intensity? A. It causes the field intensity to increase. B. It causes the field intensity to decrease. C. It causes the field intensity to fluctuate up and down. D. It has no effect on field intensity.

B

436. Most materials' relative permittivity lies between A. 0.01 - 1 B. 1 - 10 C. 10 - 50 D. 50 - 100

B

437. Charge body at rest is said to exhibit electric field, which interacts with other bodies. The study of this phenomena is known as A. electricity B. electrostatics C. electromagnetism D. field interactions

B

439. The force between the two electrically charged body is called A. electromotive force B. electrostatic force C. electromagnetic force D. magnetic force

B

442. Determine the force in Newton between 4μC charges separated by 0.1 meter in air. A. 1.44 N B. 14.4 N C. 144 N D. 1440 N

B

444. The value of k in Coulomb's electrostatic force equation ( F = kQ1Q2/r^2 ) is oftentimes expressed as 1/4πεο. What is εο? A. absolute permeability B. absolute permittivity C. relative permeability D. relative permittivity

B

451. What do you call the phenomenon whereby substance attracts pieces of iron? A. Permeability B. Magnetism C. Naturalism D. Electromagnetism

B

459. What do you call a pole that when place in air with a similar and equal pole will cause a force of repulsion of 1/4πμο Newtons? A. South Pole B. Unit pole C. Convergence pole D. Universal Pole

B

461. The phenomenon in which a substance becomes a magnet when placed near a magnet. A. magnetic transfer B. magnetic induction C. electromagnetism D. magnetism

B

468. Ability of a material to conduct magnetic flux through it refers to A. permittivity B. permeability C. reluctivity D. conductivity

B

469. The ability to concentrate magnetic lines of force. A. retentivity B. permeability C. susceptability D. reluctivity

B

471. The ratio of material permeability to the permeability of air or vacuum. A. relative conductivity B. relative permeability C. inverse permeability D. inverse permittivity

B

472. What is the relative permeability of air? A. 0 B. 1 C. 4π x 10^-7 H/m D. 8.854 x 10^-12 F/m

B

474. Materials with permeability slightly greater than that of free space. A. diamagnetic B. paramagnetic C. ferromagnetic D. antimagnetic

B

478. Nonmetallic materials that has ferromagnetic properties. A. termites B. ferrites C. ferrous D. loadstone

B

481. Cobalt is an example of a _________ material. A. diamagnetic B. ferromagnetic C. paramagnetic D. magnetic

B

484. What do you call the total number of magnetic lines of force in a magnetic field? A. magnetic field B. magnetic flux C. magnetic flux density D. magnetic lines of force

B

492. Calculate the flux density in Gauss (G) having a flux of 12,000 Mx through a perpendicular area of 6cm. A. 200 G B. 2,000 G C. 7,200 G D. 72,000 G

B

494. The capacity of a substance to become magnetized. This is expressed as a ratio between the magnetization produced in a substance to the magnetizing force producing it. A. magnetic conductivity B. magnetic susceptibility C. magnetic resistivity D. magnetic reluctivity

B

495. The typical saturation flux density for most magnetic materials. A. 0.1 Wb/m^2 B. 2 Wb/m^2 C. 10 Wb/m^2 D. 20 Wb/m^2

B

496. The force between two magnetic poles is _________ permeability of the medium. A. directly proportional to the B. inversely proportional to the C. not dependent of the D. exponentially proportional to the

B

498. A force of 20 N is acting on a 10 Wb magnetic pole, calculate the intensity of the magnetic field? A. 0.5 N/Wb B. 2 N/Wb C. 10 N/Wb D. 20 N/Wb

B

500. The unit of permittivity A. Henry/meter (H/m) B. Farad/meter (F/m) C. Henry-meter (H-m) D. Farad-meter (F-m)

B

505. The equivalent of 1 x 10^9 Maxwells is A. 1 Weber B. 10 Weber C. 100 Weber D. 1,000 Weber

B

507. The unit of flux density in mks A. Gauss B. Weber/m^2 C. Maxwell D. Tesla

B

509. Voltage in electrical circuits is analogous to _________ in magnetic circuits. A. Ampere-turn B. Magnetomotive force C. Magnetizing force D. Flux

B

511. __________ capability is analogous to permeance. A. Admittance B. Conductance C. Reluctance D. Resistance

B

516. Is the reciprocal of reluctance and implies the readiness of a material to develop magnetic flux. A. elastance B. permeance C. susceptance D. conductance

B

517. Magnetic circuit property that permits flux. A. elastance B. permeance C. susceptance D. conductance

B

525. One Gilbert is equal to A. 0.0796 At B. 0.796 At C. 7.96 At D. 79.6 At

B

526. One Ampere-turn (At) is equivalent to A. 0.126 Gilbert B. 1.260 Gilberts C. 12.60 Gilberts D. 126 Gilberts

B

528. Determine the ampere-turns when a 10 V battery is connected across a solenoid having 100 turns and a resistance of 5 Ω. A. 50 At B. 200 At C. 100 At D. 1,000 At

B

529. What is residual magnetism? A. The external magnetic field when the current is flowing through the exciting coil. B. The flux density, which exist in the iron core when the magnetic field intensity is reduced to zero. C. The flux density, which exist in the iron core when the magnetic field intensity is at its maximum value. D. The flux density when the magnetic core is saturated.

B

538. Magnetic flux can always be attributed to A. static charged particles B. motion of charge particles C. static electric field D. every applied potential

B

541. The magnetic flux around a straight, current carrying wire, is stronger A. near the edge B. near the wire C. at the center D. at both edge

B

547. What is the law whereby the force of attraction or repulsion between poles is inversely proportional to the square of the distance between them? A. Coulomb's first law B. Coulomb's second law C. Coulomb's third law D. Coulomb's law

B

550. A changing magnetic field A. produces an electric field B. induces potential C. produces a fluctuating electric field D. produces a steady electric field

B

6. If the resistance of a material 2 m long and 2 mA2 in area of cross-section is 1.6 x10A8 n, then its resistivity is A. 3.2 x 10A-8 n-m B. 1.6 x 10"-8 0-m C. 0.64 x 10A-8 nm D. 0.16 x 10A-8 n-m

B

7. If two similar charges 1 coulomb each are placed 1 m apart in air, then the force of repulsion is A.8 x 10A6 N B. 9 x 1 "9 N C. 10A6 N D. 5 x 10A6 N

B

9.The direction of force o a current carrying conductor placed in a magnetic field can be found by A. Cork screw rule B. Fleming's left hand rule C. Fleming's right hand rule D. using a compass

B

A 200-watt lamp working for 24 hours will consume approximately units. A. 50 B. 5 C. 24 D. 0.5

B

A germanium atom has an atomic weight of 72. How many neutrons are there? A. 32 B. 40 C. 34 D. 36

B

A magnetic field is A. The current flow through space around a permanent magnet B. The force set up when current flows through a conductor C. The force that drives current through a resistor D. The force between the plates of a charged capacitor

B

A magnetic flux of 2.5 x10'4 Wb through an area of 5 x10'4 square meters results in A. 5 Wb B. 0.5 Tesia of flux density C. 5x 10'-5 Wb of flux D. 5000 Tesia of flux density

B

A principle that states that only two electrons with different spins are allowed to exist in a given orbit A. Bohr's principle B. Pauli exclusion principle C. Avogadro's principle D. Coulomb's principle

B

Amorphous solid is also called A. Crystalline B. Non- crystalline C. Polycrystalline D. Homogenous

B

At/m is a unit of A. mmf B. magnetic force C. reluctance D. magnetic flux density

B

Core materials of a good relay have hysteresis loop. A. large B. narrow C. very large D. very narrow

B

Defined as a closed path in which magnetic induction or flux flows A. Electric circuit B. Magnetic circuit C. Electronic circuit D. Electromagnetic circuit

B

If the distance between two magnetic poles decreases by 2 times, the force between them A. decreases two times B. increases four times C. increases two times D. decreases four times

B

If the solenoid is gripped by the right hand with the fingers pointing the direction of current flow, the outstretched thumb will then point the north pole. This is known as A. Right hand rule B. Helix rule C. End rule D. Cork screw rule

B

If the value of a25 a conductor is 1/255 per o C, then the value of a20 is A. 1/300 per oC B. 1/250 per oC C. 1/230 per oC D. 1/260 per oC

B

One ampere- turn is equivalent to gilberts A. 1.16 B. 1.26 C. 1.36 D. 1.46

B

One that has magnetic poles produced by internal atomic structure with no external current necessary A. Diamagnetic B. Permanent magnets C. Paramagnetic D. Electromagnetic

B

Permanent magnets can be found in A. electric bells B. earphones C. relays D. dynamic loudspeakers

B

Residual magnetism refers to the flux density, which exists in the iron core when the magnetic field intensity is A. Minimized B. Reduced to zero C. Maximize D. Unity

B

Temporary magnets are commonly employed in A. electric instruments B. motors C. moving coils loudspeakers D. magnetos

B

The B-H curve for is a straight line passing through the origin. A. cobal t B. air C. hardened steel D. soft iron

B

The K shell or the first shell has how many permissible number of orbiting electrons? A. I B. 2 C. 3 D. 4

B

The branch of Engineering which deals with the magnetic effect of electric current is known as A. Magnetism B. Electromagnetism C. Electrical engineering D. Electronics engineering

B

The contribution to the ionization in an ionization chamber by electrons liberated from the walls. A. Skin effect B. Walt effect C. Hall effect D. Edison effect

B

The current of electric circuit is analogous to which quantity of a magnetic circuit A. Mmf B. Flux C. Flux density D. Reluctivity

B

The electric flux density is a quantity. C. 90 o A. phasor B. vector C. scalar D. variable

B

The electric potential across part AB of a circuit is 5 V; point A being at higher potential. If a charge of 5 C moves from A to B, then energy released as A. 5 joules B. 25 joules C. 10 joules D. 100 joules

B

The electrons in the last orbit of an atom are called ------- electrons. A. free B. valence C. bound D. thermionic

B

The emission of electrons from hot bodies is called A. Radiation effect B. Edison effect C. Skin effect D. Half effect

B

The force between two charges placed a given distance apart as the relative permittivity of the medium is increased. A. increases B. decreases C. remains unchanged D. becomes infinite

B

The force between two magnetic poles is their polesstrength. A. equal to B. directly proportionalto C. inversely proportional to D. directly proportional to the square root of

B

The greater percentage of materials is . A. diamagnetic B. paramagnetic C. ferromagnetic D. non-magnetic

B

The magnetic field around the conductor is determined by the A. Size of the conductor B. Amount of current C. Current divided by the resistance D. Resistance divided by the current

B

The magnetic field inside a solenoid A. is zero B. is uniform C. increases with distance from the axis D. decreases with distance from the axis

B

The magnetic flux of 2000 lines is how many Maxwells? A. 1000 B. 2000 C. 4000 D. 8000

B

The magnitude of the induced emf in a coil is directly proportional to the rate of change of flux linkages. This is known as A. Joule's Law B. Faraday's second law of electromagnetic induction C. Faraday's first law of electromagnetic induction D. Coulomb's Law

B

The mass of proton is the mass of an electron. A. equal to B. about 1837 times C. less than D. 200 times

B

The permeability of a material having a flux density of 5 Wb/mA2 is 10A-5 H/m. What is the value of magnetizing force? A. 5 x 10A-5 N/Wb B. 500 X 10"3 N/Wb C. 4n x 10A-7 N/Wb D. 4n x 10A7 N/Wb

B

The property of a material which opposes the creation of magnetic flux in it A. Resistance B. Reluctance C. Permeance D. Conductance

B

The reluctance of the magnetic circuit is _ relative permeability of the material comprising the circuit. A. directly proportional to B. inversely proportional to C. independent of D. dependent of

B

The simplest type of atom to exist is the atom. A. Helium B. Hydrogen C. Boron D. Oxygen

B

The temperature coefficient of resistance of insulators is A. zero B. negative C. positive D. infinite

B

The unit of flux density is A. Wb/m B. Tesla C. At/m D. N/Wb

B

Under ordinary conditions, a body is considered A. positively charged B. neutral C. negatively charged D. stable

B

What bond is formed when electrons in the outermost energy orbits of the atoms are shared between two or more electrons? A. Ionic B. Covalent C. Metallic D. Van der Waals

B

What is the SI unit of magnetic flux? A. Tesla B. Weber C. Maxwell D. Gauss

B

What is the practical unit of electrical energy? A. Watt B. Kilowatt-hour C. Kilowatt-second D. Megawat-hour

B

What is the relative permittivity of air? A. 0 B. 1 C. 8.854 x 10A12 D. 41 x 10A-7

B

What is used as the insulating material or dielectric in an electric ion? A. Oiled paper B. Mica C. Paraffin D. Titanate compound

B

What principle states that each electron in an atom must have a different set of quantum numbers? A. Inclusion principle B. Exclusion principle C. Quantum principle D. Electron principle

B

What solid has no defined crystal structure except perhaps in the arrangement of the nearest neighboring atoms or ions? A. Crystalline B. Amorphous C. Polycrystalline D. Poly- amorphous

B

When a wire loop is rotated in a magnetic field the direction of the induced emf changes one in every revolution A. 1/3 B. 1/2 C. 1/4 D. 2/3

B

When the ferromagnetic substance is inserted in a current- carrying solenoid, the magnetic field is A. Greatly decreased B. Greatly increased C. Slightly decreased D. Slightly increased

B

When the relative permeability of a material is much greater than 1, it is called material. A. diamagnetic B. ferromagnetic C. paramagnetic D. non-magnetic

B

Which of the following is a vector quantity? A. Magnetic potential B. Magnetic field intensity C. Magnetic permeability D. Flux density

B

Which of the following materials has the least hysteresis loop area? A. soft iron B. silicon steel C. hard steel D. wrought iron

B

Which of the following statements is TRUE? A. Silicon dioxide is a good B. The current carriers in conductors are valence electrons C. For conductors, the valence electron are strongly attracted to the nucleus D. The valence electrons are located in the nucleus of an atom

B

Who discovered the relationship between magnetism and electricity that serves as the foundation for the theory of electromagnetism? A. Luigi Galvani B. Hans Christian Oersted C. Andre Ampere D. Charles Coulomb

B

. An effect which is generally used in the gausameter to measure flux density. A. Skin effect B. Magnetic effect C. Hall effect D. Flywheel effect

C

. The electric field intensity between the parallel plate air capacitor is 20 N/C. If an insulating slab of relative permittivity 5 is placed between the plates, then electric field intensity will be A. 20 N/C B. 100 N/C C. 4 N/C D. 40 N/C

C

. is a substance of whose molecules consist of the same kind of atom. A. Mixture B. Compoun d C. Element D. Isotope

C

.A negatively charge body has A. deficit of electrons B. excess of protons C. excess of electrons D. deficit of neutrons

C

.An alloy of 40 percent iron and 60 percent nickel. A. Alnico B. Permallo y C. Hipernik D. Manganin

C

.Hysteresis is a phenomenon of in a magnetic circuit. A. setting up constant flux B. lagging of H behind B C. lagging B behind H D. leading B ahead H

C

.If the length and area of cross-section of a wire are doubled, then its resistance A. becomes four times B. becomes sixteen times C. remains the same D. becomes two times

C

.If the relative permittivity of a material is 10, then its permittivity is A. 41 x 10A-7 F/m B. 41 x 10A-6 F/m C.8.854 x 1 "-11 F/m D.8.854 x 10A-12 F/m

C

.Magnetic field intensity is a quantity. A. scalar B. phasor C. vector D. variable

C

.The relative permeability of a magnetic material is 10A5. What is its permeability? A. 4n x 10A5 H/m B. 4n x 10A-12 H/m C. 41 t x 10 - H m D. 4n x 10A-7 H/m

C

.The resistance of a material is its area ofcross-section. A. directly proportional B. independent of C. inversely proportionalto D. equal to

C

.What is the unit of magnetomotive force? A. Volt B. Tesla C. Ampere- turn D. Weber

C

0hm's law cannot be applied to which material? A. Copper B. Silver C. Silicon carbide D. Aluminum

C

1.How is mutual inductance between two coils decreased? A. By using a common core B. By moving the coils closer C. By moving the coils apart D. By increasing the number of turns of either coil

C

306. The lightest kind of atom or element A. Helium B. Oxygen C. Hydrogen D. Titanium

C

319. The discrete amount of energy required to move an electron from a lower shell to a higher shell. A. negative energy B. positive energy C. quantum D. quanta

C

323. In an atomic structure, what particle that has no charge and therefore has no effect on its atomic charge A. electrons B. protons C. neutrons D. nucleons

C

324. The atomic number of an element is determined by the number of A. electrons B. valence electrons C. protons D. protons or neutrons

C

326. If an element has an atomic number of 12, there are how many protons and electrons? A. 6 protons and 12 electrons B. 12 protons and 6 electrons C. 12 protons and 12 electrons D. 12 protons and 24 electrons

C

334. What elements possess four valence electrons? A. Insulators B. Semi-insulators C. Semiconductors D. Conductors

C

340. A material that contains an abundance of free carrier is called A. insulator B. semi-insulator C. conductor D. semiconductor

C

343. __________ has a unit of electronvolt(eV). A. Charge B. Potential difference C. Energy D. Current

C

346. The energy gap of an insulator is in the order of A. zero electron volt (0 eV) B. one electron volt (1 eV) C. five electron volt (5 eV) D. one-tenth electron volt (0.1 eV)

C

352. What will happen to an atom if an electron is either taken out or taken into the same atom? A. Becomes negative ion B. Becomes positive ion C. Becomes an ion D. Nothing will happen

C

353. When an atom gains an additional _________, it results to a negative ion. A. neutron B. proton C. electron D. atom

C

356. Dielectric is another name for A. conductor B. semiconductor C. insulator D. semi-insulator

C

360. The particles that make up the lattice in ionic crystal A. molecules B. ions C. electrons D. neutrons

C

369. A negative ion results when an atom A. loss some of its inside electrons B. loss some of its valence electrons C. gains additional electron D. gains additional proton

C

370. A positive ion has A. excess of electrons B. excess of neutrons C. lack of electrons D. lack of protons

C

371. What do you call a positively charged ion? A. cathode B. anion C. cation D. domain

C

373. __________ is the procedure by which an atom is given a net charge by adding or taking away electron. A. Polarization B. Irradiation C. Ionization D. Doping

C

381. What is the charge magnitude, Q of a body if it lacks 5 electrons? A. 5 x 10^-19 Coulomb B. 5 Coulomb C. 8 x 10^-19 Coulomb D. 19 x 10^-19 Coulomb

C

386. When one coulomb of electric charge continuously passes a given point every second, the electric current is said to A. 1 µA B. 1 mA C. 1 A D. 10 A

C

389. If in a material, current can hardly pass, it means A. the material is very hard B. the material is very soft C. the material has high resistance D. the material has less resistance

C

395. A 100m long wire with a cross-sectional area A=10-3 m2 has a resistance of 10Ω. Determine the resistivity of the wire. A. 10^-2 Ω-m B. 10^-3 Ω-m C. 10^-4 Ω-m D. 10^-5 Ω-m

C

398. What happens in the resistance of copper wire when its temperature is raised? A. decreased B. steady C. increased D. zero

C

402. ________ is one factor that does not affect resistance. A. Cross sectional area B. Resistivity C. Mass D. Length

C

405. Find the charge in coulombs of dielectric that has a positive charge of 14.5 x 10 to the 18th power protons. A. 29 x 10 to the 16th Coulombs B. 14.5 x 10 to the 16th Coulombs C. 14.5 x 10 to the 18th Coulombs D. 29 x 10 to the 18th Coulombs

C

419. The number of lines per unit area in a plane perpendicular to the electric lines of force. A. Electric field B. Electric flux C. Electric flux density D. Electric lines of force

C

429. The ability of the material to store electrical potential energy under the influence of an electric field. A. capacity B. permeability C. permittivity D. conductivity

C

446. Calculate the electric field intensity 10cm from a charge Q = 5nC. A. 450 N/C B. 900 N/C C. 4.5 x 10^3 N/C D. 9.0 x 10^3 N/C

C

448. Calculate the total electric field at the surface of a sphere of radius r = 1cm, and enclosing a net charge of 2 μC. A. 0 (zero) B. 9 x 10^7 N/C C. 1.8 x 10^8 N/C D. infinite

C

452. The condition in which a substance attracts pieces of iron is known as A. Electromagnetism B. Electrolysis C. Magnetism D. Magnetic Induction

C

454. A natural magnet A. loadstone B. carbon C. lodestone D. magnesium

C

455. Group of magnetically aligned atoms. A. Lattice B. Crystal C. Domain D. Range

C

457. Which of the following refers to a characteristic of a magnetic line of force? A. Travels from south to north through the surrounding medium of a bar magnet B. Travels back and forth between the north and south pole of a bar magnet C. Travels from north to south through the surrounding medium of a bar magnet D. Stay stationary between the north and the south of a bar magnet

C

465. A substance having high retentivity is best suited in making A. an electromagnet B. a temporary magnet C. a permanent magnet D. two pole magnet

C

475. What do you call materials, which possess very high permeabilities? A. diamagnetic B. paramagnetic C. ferromagnetic D. antimagnetic

C

485. The number of lines per unit area in a plane perpendicular to the magnetic lines of force. A. magnetic field B. magnetic flux C. magnetic flux density D. magnetic lines of force

C

486. The direction of field lines outside a magnet is A. from north to south pole B. from south to north pole C. either from north to south or south to north pole D. dependent on the magnet's orientation with respect to the earth's magnetic pole

C

487. The entire group of magnetic field lines flowing outward from the north pole of a magnet. A. magnetic field B. magnetic flux density C. magnetic flux D. electromagnetic field

C

488. Magnetic lines of force are called A. magnetic field B. magnetic flux density C. magnetic flux D. electromagnetic field

C

493. What does a gauss meter measure? A. flux B. magnetic field C. magnetic flux density D. mmf

C

503. What is the unit of flux in cgs? A. Ampere-turn (At) B. Coulomb/sec. (C/s) C. Maxwell (Mx) D. Gauss

C

508. What do you call the force that sets up or tends to set up magnetic flux in a magnetic circuit? A. electromotive force B. potential difference C. magnetomotive force D. dynamic force

C

520. The unit of reluctance A. Gilbert B. Tesla C. At/Wb D. Gauss

C

521. It is the specific reluctance of a material. A. resistivity B. retentivity C. reluctivity D. permeability

C

522. At/m is a unit of A. magnetic field B. reluctance C. magnetizing force D. magnetic power

C

524. The cgs unit of magnetomotive force A. Volt B. Weber C. Gilbert D. Ampere-turn

C

530. When you demagnetize property by applying an AC field and then gradually reduced it to zero, it is called A. damping B. decaying C. degaussing D. gaussing

C

537. Electromagnet whose core is in the form of a close magnetic ring A. solenoid B. relay C. toroid D. circular

C

549. What law in electronics where an induced current will be in such a direction that its own magnetic field will oppose the magnetic field that produces the same? A. Electromagnetic law B. Norton's law C. Lenz law D. Maxwell law

C

A 6- V battery is connected across a solenoid of 100 turns having a resistance of 2 n, Calculate the number of ampere turns? A. 100 B. 50 C. 300 D. 600

C

A group of magnetically aligned atoms is called A. Range B. Lattice C. Domain D. Crystal

C

A law establishing the fact that the algebraic su of the rises and drops of the mmf around a closed loop of a magnetic circuit is equal to zero. A. Kirchhoff's circuital law B. Maxwell's circuital law C. Ampere's circuital law D. Coulomb's circuital law

C

A law that states that the current in a thermionic diode varies directly with the three- halves power of anode voltage and inversely with the square of the distance between the electrodes, provided operating conditions are such that the current is limited only by the space charge. A. Hall's law B. Joule's law C. Child's law D. Coulomb's law

C

A length of wire has a resistance of 10 ohms. What is the resistance of a wire of the same material three times as long and twice the cross-sectional area? A. 30 ohms B. 20 ohms C. 15 ohms D. 7 ohms

C

A substance that attracts pieces iron A. Conductor B. Semiconductor C. Magnet D. All of the above

C

A test charge means a charge of A. -1 C B. 1 electron C. +1 C D. -20 C

C

An atom or a group of atoms that carries a net electric charge. A. Positive ion B. Negative ion C. Ion D. Electron

C

Another term for corona discharge. A. Lightning B. Sparkin g C. Aurora D. Corona Effect

C

As the magnetic intensity decreases, the relative permeability of a magnetic material A. decreases B. remains the same C. increases D. becomes zero

C

Calculate the flux density that will be produced by the field intensity of 2000 a. t/m for a permeability of 126 x 10'-6 T/A.t/m A. 0.252 G B. 0.252 x 10'-2 T C. 0.252 T D. 0.252 x 10'-2 G

C

Cobalt is an example of a material. A. Paramagnetic B. Diamagnetic C. Ferromagnetic D. Non- magnetic

C

Define as that pole which when placed in air from a similar and equal pole repels it with a force of newtons A. North pole B. South pole C. Unit pole D. Magnetic pole

C

Defined as the number of lines per unit area through any substance in a plane at right angles to the lines of force A. Flux B. Flux lines C. Flux density D. Flux intensity

C

Electric field intensity at a point due to a given charge if the relative permittivity of the medium decreases. A. decreases B. remains unchanged C. increases D. becomes zero

C

Electric field intensity is a . A. scalar B. phasor C. vector D. variable

C

Electric lines of force leave or enter the charge surface at an angle of A. 30o B. 45 o C. 90 o D. depending upon the angle of launch and entry

C

How many neutrons does a copper atom have? A. 32 B. 33 C. 34 D. 29

C

How many turns are needed to produce a magnetomotive force of 1000 A.t for a coil with 6 amperes? A. 6000 turns B. 600 turns C. 167 turns D. 67 turns

C

If the number of valence electrons of an atom is more than 4, the substance is called A. a semiconductor B. a conductor C. an insulator D. a semi-insulator

C

If the right handed bottle-opener cork screw is assumed to be along the conductor so as to advance in the direction of current flow, the motion of its handle will indicate the direction of magnetic flux produced around the conductor. This is known as A. Right hand rule B. Left hand rule C. Cork screw rule D. End rule

C

It is the reciprocal of reluctance and implies the case of readiness with which magnetic flux is developed. A. Resistance B. Conductanc e C. Permeance D. Inductance

C

Magnetic effects of the earth as a huge magnet with north and south poles. A. Diamagnetic B. Ferromagnetic C. Terrestrial magnetism D. Terrestrial ferromagnetism

C

Materials that have very high permeabilities (hundreds and even thousands times of that of free space) A. Paramagnetic B. Non- magnetic C. Ferromagnetic D. Diamagnetic

C

Paramagnetic substance has a relative permeability of A. Slightly less than one B. Equal to one C. Slightly equal to one D. Very much greater than one

C

Small voltages generated by a conductor with current in an external magnetic field. A. Skin effect B. Magnetic effect C. Hall effect D. Flywheel Effect

C

The ability of a mechanically stressed ferromagnetic wire to recognize rapid switching of magnetization when subjected to a dc magnetic field. A. Wartheim effect B. Wiedemann effect C. Wiegand effect D. Edison effect

C

The amount of magnetizing force to counter balance the residual magnetism of a magnetic material is referred to as A. Reluctivity B. Susceptivity C. Coercivity D. Retentivity

C

The customary energy unit in atomic and nuclear physics is A. Joule B. Voltcoulomb C. electron-volt D. Walt- second

C

The diameter of a hydrogen atom is approximately cm. A. 1.1 x 1Q'-6 B. 1.1 x 1Q'-7 C. 1.1 x 10"-8 D. 1.1 x 1Q'-9

C

The electric potential at a point in air due to a charge is 21 V. If the air is replaced by a medium of relative permittivity of 3, then electric potential at that point will be A. 63 V B. 21 V C. 7 V D. 42 V

C

The energy stored in an electrostatic field or electromagnetic field is called A. Electromagnetic energy B. Kinetic energy C. Potential energy D. Rest energy

C

The evaporation of electrons from a heated surface is called A. Radiation B. Convection C. Thermionic emission D. Conduction

C

The force between two magnetic poles is the relative permeability of the medium. A. directly proportional to B. independent of C. inversely proportionalto D. equal to

C

The force of attraction or repulsion between two magnetic poles is directly proportional to their strengths. A. Newton's first law B. Faraday's first law of electromagnetic induction C. Coulomb's first law D. Coulomb's second law

C

The idea of preventing one component from affecting another through their common electric and magnetic field is referred to as A. Hall effect B. Groundin g C. Shielding D. Limiting

C

The lagging effect between flux density of the material and the magnetizing force applied A. Permeance B. Eddy current C. Hysteresis D. Reluctance

C

The magnetic energy stored in an inductor is current. A. Directly proportional to B. Inversely proportional to C. Directly proportional to the square of D. Inversely proportional to the square of

C

The magnetic flux through a wire loop in a magnetic field does not depend on A. The area of the loop B. The magnitude of the field C. The shape of the loop D. The angle between the plane of the loop and the direction

C

The magnetic materials should have a large hysteresis loss for one of the following applications. A. Transformers B. AC motors C. Permanent Magnets D. DC generators

C

The phenomenon by which a magnetic substance becomes a magnet when it is place near a magnet A. Magnetic effect B. Magnetic phenomenon C. Magnetic induction D. Electromagnetic induction

C

The quantity of magnetism retained by a magnetic material after withdrawal of the magnetizing force is called A. Leftover magnetism B. Hysteresis C. Residual magnetism D. Coercivity

C

The ratio between the intensity of magnetization produced in a substance to the magnetizing force producing it A. Magnetic Reluctivity B. Magnetic Resistivity C. Magnetic susceptibility D. Magnetic conductivity

C

The reluctance of a magnetic circuit is not dependent on which of the following? A. Number of turns of coil B. Magnetomotive force C. Flux density in the circuit D. Current in the coil

C

The reluctance of a magnetic circuit varies with A. length x area B. area -- length C. length + area D. length + area

C

The straight line passing through the two poles of magnet is called A. Real axis B. Cartesian axis C. Magnetic axis D. Imaginary axis

C

The temperature coefficient of resistance of eureka is A. positive B. negative C. almost zero D. infinite

C

The temperature coefficient of resistance of semiconductors is A. positive B. zero C. negative D. infinite

C

The unit of flux is in cgssystem. A. Tesia B. Gilbert C. Maxwell D. Oersted

C

Used to maintain strength of magnetic field A. Container B. Air gap C. Keeper D. Source

C

What is the SI unit of specific resistance or resistivity? A. Ohm-circular mil per inch B. Ohm-circular mil per foot C. Ohm-m D. Ohm-cm

C

What is the maximum number of electrons that can be accommodated in the last orbit of an atom? A. 4 B. 2 C. 8 D. 18

C

What is the unit of reluctance? A. Maxwell B. Gauss C. At/Wb D. Weber

C

What is the value of the absolute permittivity of air? A. 8.854 µF/m B. 8.854 x 10'-12mF/m C. 8.854 x 10A12 F/m D. 8.854 x 10'-12 µF/m

C

What is used as the dielectric material in high voltage transformers? A. Mica B. Paraffin C. Porcelain D. Oiled paper

C

What revolves about the positive nucleus in a definite orbit? A. Atom B. Proton C. Electron D. Neutron

C

What type of bond is formed when there exists some form of collective interactions between the (negatively charged) electrons and (positively charged) nuclei in a solid? A. Ionic B. Covalen t C. Metallic D. Van der Waals

C

When the relative permeability of a material is slightly more than 1, it is called material. A. diamagnetic B. ferromagnetic C. paramagnetic D. non-magneti

C

Whenever a conductor cuts magnetic flux, an emf is induced in it. This is known as A. Coulomb's law B. Joule's law C. Faraday's law D. Ohm's law

C

Whenever a flux inking a coil or current changes, an emf is induced in it. This is known as A. Joule's Law B. Coulomb's Law C. Faraday's first law of electromagnetic induction D. Faraday's second law of electromagnetic induction

C

Which element has four valence electrons? A. Conductor B. Insulator C. Semiconductor D. Semi- insulator

C

Which of the following is a diamagnetic material? A. Aluminum B. Silve r C. Air D. Cobalt

C

Which of the following is a natural magnet? A. Steel B. Magnesia C. Lodestone D. Soft iron

C

Which of the following is used by temporary magnets as the magnetic material? A. Hardened steel B. Cobalt steel C. Soft iron D. Tungsten steel

C

Who developed the electromagnetic theory of light in 1862? A. Heinrich Rudolf Hertz B. Wilhelm Rontgen C. James Clerk Maxwell D. Andre Ampere

C

is an electromagnet with its core in the form of a close magnetic ring. A. Solenoid B. Paraboloid C. Toroid D. Cycloid

C

. Hysteresis refers to the between flux density of the material and the magnetizing force applied. A. Leading effect B. Ratio C. Equality D.

D

. Magnetic fields do not interact with A. Moving permanent magnets B. Stationary permanent magnets C. Moving electric charges D. Stationary electric charges

D

. States that the ratio of the thermal conductivity is proportional to the absolute temperature for all metals. A. Wien's displacement law B. Hartleys law C. Hall's law D. Wiedemann Franz law

D

. The force of attraction or repulsion between two magnetic poles is inversely proportional to the square of the distance between them. This is known as A. Newton's first law B. Faraday's first law of electromagnetic induction C. Coulomb's first law D. Coulomb's second law

D

.A theorem which states that an electric current flowing in a circuit produces a magnetic field at external points equivalent to that due to a magnetic shell whose bounding edge is the conductor and whose strength of the current. A. Joule's law B. Faraday's law C. Volta's theorem D. Ampere'stheorem

D

.The unit of electrical energy is A. Joule B. Watt- second C. Kilowatt- hour D. All of these

D

.What is the typical saturation flux density for most magnetic materials? A. 4 Wb/mA2 B. 5 Wb/mA2 C. 1 Wb/mA2 D. m

D

.Which of the following is a paramagnetic material? A. Carbon B. Copper C. Bismut h D. Oxygen

D

.Which of the following is used by permanent magnets as the magnetic material? A. iron B. nickel C. soft steel D. hardened steel

D

0ne weber of flux is equal to magnetic lines of force. A. 1 6 B. 1 1 C. x 1 7 D. 10"8

D

1.Electric field intensity at a point is numerically equal to at that point. A. potential gradient B. potential difference C. dielectric constant D. the force

D

302. Which of the following is not a basic part of an atom? A. Electron B. Proton C. Neutron D. Coulomb

D

305. Approximate diameter of an atom A. 10^-10 µµm B. 10^-10 µm C. 10^-10 mm D. 10^-10 m

D

309. A commonly used model in predicting the atomic structure of a material. A. String model B. Wave model C. Particle model D. Bohr model

D

310. Is at the center of an atomic structure in a Bohr model. A. electrons B. protons C. neutrons D. nucleus

D

317. Approximately, how many electrons that could equal to the mass of a single proton or neutron? A. 1,863 electrons B. 1,683 electrons C. 1,638 electrons D. 1,836 electrons

D

321. Electron is derived from the Greek name elektron which means A. huge B. tiny C. particle D. amber

D

322. Electric charge of neutron is the same as A. proton B. electron C. current D. atom

D

325. The atomic weight of an element is determined by the number of A. electrons B. valence electrons C. protons D. protons and neutrons

D

327. Suppose there is an atom containing eight protons and eight neutrons in the nucleus, and two neutron are added to the nucleus, the resulting atomic weight is about A. 8 B. 10 C. 16 D. 18

D

328. It is composed of a series of energy levels containing the valence electrons. A. conduction band B. forbidden band C. side band D. valence band

D

330. _____________ are electrons at the outer shell A. Inside shell electrons B. Conductor electrons C. Outside shell electrons D. Valence electrons

D

337. An insulating element or material has capability of _________. A. conducting large current B. storing voltage C. storing high current D. preventing short circuit between two conducting wires

D

338. A law of nature makes certain materials tend to form combinations that will make them stable. How many electrons in the valence orbit are needed to give stability? A. 1 B. 2 C. 4 D. 8

D

347. In materials, what do you call the region that separates the valence and conduction bands? A. energy gap B. forbidden band C. insulation band D. energy gap or forbidden band

D

348. What do you call the potential required to remove a valence electron? A. valence potential B. threshold potential C. critical potential D. ionization potential

D

350. Copper atom has how many protons? A. 1 B. 4 C. 8 D. 29

D

358. An isotope A. has a negative charge B. has a positive charge C. might have either positive or negative charge D. is neutral

D

362. A solid, which has no defined crystal structure. A. Crystalline B. Non-crystalline C. Amorphous D. Non-crystalline or Amorphous

D

363. States that each electron in an atom must have a different set of quantum numbers. A. Quantum principle B. Fermi-Dirac principle C. Spin principle D. Exclusion principle

D

364. Given an atomic structure of a certain material, what data can you determine out from it? A. atomic number B. atomic mass C. the number of protons and electrons D. all of the above

D

374. Is a process by which an atom is constantly losing and then regaining electrons? A. oxidation B. passivation C. metallization D. ionization

D

375. The process in which atoms are changed into ions. A. oxidation B. passivation C. metallization D. ionization

D

387. One ampere is equal to how many electrons per second? A. 1 x 10^18 electrons/sec. B. 1 x 10^19 electrons/sec. C. 6.25 x 10^18 electrons/sec. D. 6.25 x 10^19 electrons/sec.

D

392. If a conductor's cross-sectional area is doubled and its length is halved, the value of its resistance will A. double B. quadruple C. decrease by a factor of two D. decrease by a factor of four

D

396. the reciprocal of resistance A. permeance B. elastance C. inductance D. conductance

D

397. The science of physical phenomena at very low temperature, approaching absolute zero is called ________. A. cryptanalysis B. cybernetics C. temperature inversion D. cryogenics

D

399. A wire has a resistance of 5Ω at room temperature and a temperature coefficient α = 4 x 10^-3/°C, calculate the wire resistance at 75°C. A. 8.925 Ω B. 7.925 Ω C. 6.925 Ω D. 6.050 Ω

D

400. The temperature coefficient of resistance of a certain wire is known to be 0.004/°C at zero degrees Celsius. What would be the temperature coefficient at room temperature? A. 0.00018/°C B. 0.00036/°C C. 0.00180/°C D. 0.00360/°C

D

404. The ability of a material to resist current flow is called "resistance". What is (are) the factor(s) that affect its value? A. temperature B. length & cross-sectional area C. atomic structure D. all of these

D

407. One electron volt (eV) is equivalent to A. 1.0 watt-sec B. 1.6 x 10^-19 watt-sec C. 1.0 Joule D. 1.6 x 10^-19 Joules

D

408. What law that describes the force of attraction or repulsion between two charges is directly proportional to their strengths and inversely proportional to the square of the distance between them? A. Coulomb's first law B. Coulomb's second law C. Coulomb's third law D. Coulomb's law or law of electrostatics

D

409. What is the law whereby the force of attraction and repulsion between poles is inversely proportional to the square of the distance between them? A. Newton's first law B. Newton's second law C. Norton's law D. Coulomb's second law

D

410. Is usually used to detect the presence of electric charge. A. experimental charge B. unit charge C. dipole D. test charge

D

412. Three charges of +5 C, -6 C and +7 C are placed inside a sphere, what is the total charge of the sphere? A. +5 Coulomb B. -6 Coulomb C. -7 Coulomb D. +6 Coulomb

D

413. A combination of two charges, with equal charge magnitude but opposite signs. A. magnetic dipole B. static dipole C. dynamic dipole D. electric dipole

D

415. Refers to a force of field that exists between ions where they either repel or attract each other. A. Resisting field B. Potential field C. Dielectric D. Electromotive

D

416. The imaginary lines representing the electric field. A. Electric field B. Electric flux C. Electric flux density D. Electric lines of force

D

417. What is true in visualizing electric field lines of force from a charge body? A. Field lines are continuous curve and they never intersect. B. The spacing between these lines increases as they get far from the charged body. C. The number of field lines is directly proportional to the magnitude of the electric field. D. All of the above.

D

420. Electric lines of force leave and enter the charge surface at what angle? A. 15° B. 30° C. 45° D. 90°

D

427. An electric charge produces a total electric field of 6 Coulombs, calculate the electric flux density in an area of one square meter (1m2). A. 1 C/m^2 B. 2 C/m^2 C. 4 C/m^2 D. 6 C/m^2

D

428. The measure of density of the electric charge A. Electric gradient B. Electric current C. Electric charge D. Electric potential

D

433. What is the term used to express the amount of electrical energy stored in an electrostatic field? A. Volts B. Watts C. Coulombs D. Joules

D

438. The basic law for interaction of charged bodies at rest. A. Charged law B. Gauss' law C. Faraday's law D. Coulomb's law

D

441. In 1784, who demonstrated that the force between charges is inversely related to the square of the distance between them? A. Maxwell B. Gauss C. Tesla D. Coulomb

D

443. What will happen when two opposite charges get closer? A. repels less B. attracts less C. repels more D. attracts more

D

445. The measure of electric field strength per unit length is known as electric field intensity or simply electric intensity. What is its unit? A. Volt/meter (V/m) B. Joules/Coulomb-meter (J/Cm) C. Newton/Coulomb (N/C) D. All of the above

D

449. A 2nC point charge will produce what potential at 2 m away? A. 4.0 Volts B. 6.0 Volts C. 7.5 Volts D. 9.0 Volts

D

456. In a magnet, what do you call the point in which the magnetic lines of force is maximum? A. maximum pole B. intensified pole C. unit pole D. magnetic pole

D

460. In a magnet, the straight line passing through the two poles is called A. real axis B. imaginary axis C. Cartesian axis D. magnetic axis

D

463. What do you call the quantity of magnetism retained by a magnetic material after the withdrawal of a magnetizing force? A. Left over magnetism B. Coercivity C. Hysteresis D. Residual magnetism

D

477. Permeability of a material means: A. The ability of the material to conduct electric field B. The conductivity of the material for electromagnetic field C. The ability of the material to hold magnetic flux D. The conductivity of the material for magnetic lines of force

D

479. Cores of magnetic equipment use magnetic material which has A. very low permeability B. moderate permeability C. low permeability D. high permeability

D

483. The imaginary lines representing the magnetic field. A. magnetic field B. magnetic flux C. magnetic flux density D. magnetic lines of force

D

490. The unit of magnetic flux density in SI: A. Gauss B. Weber C. Maxwell D. Tesla

D

497. If the distance between two magnetic poles is halve, the force between them A. decreases two times B. decreases four times C. increases two times D. increases four times

D

502. The Gauss is a unit of A. permeability B. electromagnetic force C. magnetic force D. magnetic flux density

D

506. A magnetic flux of 500,000,000 lines is equivalent to A. 5 x 10^8 Maxwells B. 5 Weber C. 500 x 10^6 MAxwells D. all of these

D

510. Electrical current is analogous to _________ in magnetic circuits. A. Ampere-turn B. Magnetomotive force C. Magnetizing force D. Flux

D

512. Resistance in electrical circuits is analogous to _________ in magnetic circuits. A. Conductance B. Permeance C. Elastance D. reluctance

D

513. The property of a material which opposes the creation of magnetic flux. A. elastance B. permeance C. susceptance D. reluctance

D

518. It is easier to establish flux line in soft iron than it is to establish them in air, this is because iron has a lower A. Permeance B. Inductance C. elastance D. reluctance

D

523. Magnetomotive force has a unit of A. Volt (V) B. Watt (W) C. Joule (J) D. Ampere-turn (At)

D

531. In a magnetic circuit, a flux that drifts away from its intended path is called A. lost flux B. linked flux C. drift flux D. leakage flux

D

532. Is the quantity of magnetizing force needed to counter balance the residual magnetism of a magnetic material. A. hysteresis B. degaussing C. retentivity D. coercivity

D

533. What do you call the loss of electrical energy in counter balancing the residual magnetism in each cycle? A. hysteresis B. magnetomotive C. leakage D. coercivity

D

536. An advantage of an electromagnet over a permanent magnet A. An electromagnet can be demagnetized B. An electromagnet is simpler C. An electromagnet is cheaper D. An electromagnet can be switched ON and OFF

D

545. Is used to maintain strength of magnetic field. A. storer B. energizer C. gausser D. keeper

D

A factor used to correct for the electrostatic forces of the more distant ions in an ionic solid. A. Avogadro's number B. Planck's constant C. Boltzmann's constant D. Madelung constant

D

A law relating between the magnetic and electric susceptibilities and the absolute temperatures which is followed b ferromagnets, antiferromagnets, non-polar ferroelectrics, antiferroelectrics and some paramagnets. A. Curie's Law B. Child's Law C. CR Law D. Curie-Weiss Law

D

A law that states that the polarity of the induced voltage will oppose the change in magnetic flux causing the induction. A. Joule's law B. Faraday's law C. Coulomb's law D. Lenz' law

D

A permanent magnet does not exert a force on A. an unmagnetized iron bar B. a magnetized iron bar C. a moving electric charge D. a stationary electric charge

D

A t/m is a unit of A. Mmf B. Emf C. Reluctance D. Magnetizing force

D

All matters (gas, liquid and solid) are composed of A. Neutrons B. Particles C. Electron s D. Atoms

D

Back emf refers to the A. Current equal to the applied emf B. Opposing emf C. Current opposing the applied emf D. Voltage opposing the applied emf

D

Bonding of atoms that is due to the force of attraction between positive ions and a group of negative ions A. Ionic bond B. Covalent Bond C. Electrostatic Bond D. Metallic bond

D

Defined as the flux density produced in it due to its own induced magnetism A. Magnetic field intensity B. Electric field intensity C. Electromagnetic field intensity D. Intensity magnetization

D

Electrons at the outer shell are called A. Outer shell electrons B. Inner shell electrons C. Semiconductor electrons D. Valence electrons

D

Flux linkages equals A. Flux times area of core B. Flux times number of turns times area of core C. Flux times number of turns times length of core D. Flux times number of turns

D

Formed when there exist distant electronic interactions between (opposite) charges present in the neighboring atoms or molecules. A. Ionic bond B. Covalent bond C. Metallic bond D. Van der Waals bond

D

Gases whose particles are charged are known as A. Conductors B. Insulators C. Gaseous Conductors D. Plasma

D

If a 20 V potential is applied across a relay coil with 50 turns having 1 Q of resistance, the total magnetomotive producing magnetic flux in the circuit is A. 10 Wb B. 50 T C. 1000 A t/m D. 1000 A.t

D

If on looking at any one end of a solenoid; the direction of current flow is found to be clockwise then the end under observation is a south pole. This is known as A. Right hand rule B. Left hand rule C. Cork screw rule D. End Rule

D

If you hold the conductor with right hand so that the stretched thumb points in the direction of the current, then encircling fingers will give the direction of magnetic lines of force round the conductor. This is known as A. Left hand cork screw rule B. Right hand cork screw rule C. Left hand rule D. Right hand rule

D

Lenz' law states that the direction of the induced emf and hence current A. Is determined by the rate of current flux B. Is found by the right hand rule C. Is found by the left hand rule D. Always opposes the cause producing it

D

Magnetic intensity is a A. Phasor quantity B. Physical quantity C. Scalar quantity D. Vector quantity

D

Ohm's law can be used only to a circuit or component. A. Unilateral B. Exponential C. Trivalen t D. Linear

D

One electron volt (1 eV) is equivalent to joules A. 1.3 x 10'-19 B. 1.4 x 10'-19 C. 1.5 x 10'-19 D. 1.6 x 10'-19

D

The B-H curve of is not a straight line. A. air B. wood C. silicon steel D. soft iron

D

The ability of a material to conduct magnetic flux through it. A. Permittivity B. Reluctivity C. Conductivity D. Permeability

D

The core of a magnetic equipment uses a magnetic material with A. Least permeability B. Low permeability C. Moderate permeability D. High permeability

D

The core of a transformer heats up when its primary is fed from an ac source because of A. permeability B. ferromagnetism C. reluctance of core D. hysteresis loss

D

The emf induced in a coil due to the change of its own flux linked with it is called A. Mutually induced emf B. Dynamically induced emf C. Statically induced emf D. Self induced emf

D

The flux density in an air-cored coil is 10 - Wb/m 2. With a cast iron core of relative permeability 100 inserted, the flux density will become A. 10 - Wb/m 2 B. 10 -2 Wb/m 2 C. 10 Wb/m 2 D. 0.1 Wb/m"2

D

The force between two magnetic poles varies with the distance between them. The variation is to the square of that distance. A. Equal B. Greater than C. Directly proportional D. Inversely proportional

D

The force which set ups or tends to set up magnetic flux in a magnetic circuit A. Dynamic force B. Electromotive force C. Potential difference D. Magnetomotive force

D

The magnetic field of a bar magnet most closely resembles the magnetic field of A. a horseshoe magnet B. a straight current- carrying wire C. a stream of electrons moving parallel to one another D. a current- carrying wire loop

D

The permittivity of a material is given by one of the following formulas. A. DE B. E/D C. D 2/E D. D/E

D

The ratio of the total flux (flux in iron path) to the useful flux (flux in air gap) A. Leakage flux B. Leakage current C. Leakage coefficient D. Leakage factor

D

The relation between absolute permittivity of air (E0), absolute permeability of air (µ0) and velocity of light (c) is given by A. µ0E0 = cA2 B. µ0E0 = c C. 1/µ0E0 =c D. 1/ c"

D

The science of adapting electronics to aerospace flight. A. Avionics B. Aerotronics C. Aerodynamic s D. Astrionics

D

The uncharged particles which have no effect on its atomic charge. A. Nucleons B. Electrons C. Protons D. Neutrons

D

There are how many compounds available in nature? A. 105 B. 1000 C. 300,000 D. Unlimited

D

What determines the value of the temperature coefficient of resistance of a material? A. length B. cross-sectional area C. volume D. nature and temperature

D

What is another name for relative permittivity? A. Dielectric strength B. Electric intensity C. Potential gradient D. Dielectric constant

D

What is the SI unit of conductivity? A. Ohms/m B. Ohms-m C. Siemens-m D. Siemens/m

D

What is the SI unit of reluctance? A. At B. At/m C. N/Wb D. At/Wb

D

What is the usual value of leakage coefficient for electrical machines? A. 0.5 to 1 B. 1 to 5 C. 5 to 10 D. 1.15 to 1.25

D

When a current carrying conductor is placed in a magnetic field, the maximum force will act on the conductor when the conductor is at an angle of to the magnetic field. A. 45o B. 60o C. 30o D. 90o

D

When the current flows, the magnetic field ...conductor is in what direction? A. The same as the current direction B. Opposite the current direction C. Omnidirectional D. In the direction determined by the left hand rule

D

Which of the following has the highest permeability? A. Soft iron B. Steel C. Air D. Permalloy

D

Which of the following is a paramagnetic material? A. Carbon B. Bismuth C. Copper D. Oxygen

D

Which of the following materials has permeability slightly less than that of free space? A. Paramagnetic B. Non- magnetic C. Ferromagneti c D. Diamagnetic

D

Who demonstrated that there are magnetic effects around every current-carrying conductor and that current-carrying conductors can attract and repel each other just likemagnets? A. Luigi Galvani B. Hans Christian Oersted C. Charles Coulomb D. Andre Ampere

D

Why is it that the magnitude of magnetomotive force required for air gap is much greater than that required for iron part of a magnetic circuit? A. Because air is a gas B. Because air has the highest relative permeability C. Because air is a conductor of magnetic flux D. Because air has the lowest relative permeability

D