Exam 3 -Phys

Select all the factors below that affect the magnitude of the induced voltage in a wire during an electromagnetic induction. -the number of wire loops passing though the magnetic field -the rate at which the magnetic field lines pass through the wire -the strength of magnetic field -the direction of the coils (clockwise and counter)

-the number of wire loops passing though the magnetic field -the rate at which the magnetic field lines pass through the wire -the strength of magnetic field

Consider an electrical transformer has 10 loops on its primary coil and 20 loops on its secondary coil. What is the current in the secondary if the current is the primary coil is 5.0 A?

2.5 A

Consider an electrical transformer has 10 loops on its primary coil and 20 loops on its secondary coil. What is the voltage in the secondary coil if the primary coil is supplied with 120 V?

240 Volts

A neutrally charged atom that gains one or more electrons is called a(n) A) negative ion. B) positive ion. C) deionized atom. D) positron.

A) negative ion.

Polarized light vibrates A) only in one plane. B) in two planes at right angles to one another. C) in all planes. D) not at all.

A) only in one plane

The image formed by a plane mirror is A) virtual B) real C) a result of diffuse reflection D) smaller than the object

A) virtual

The speed of light is 3.00 x 108 m/s. If the index of refraction of glass is 1.50, The speed of light in glass is A. 2.00 x 108 m/s. B. 0.50 x 108 m/s. C. 4.50 x 108 m/s. D. 3.00 x 108 m/s.

A. 2.00 x 108 m/s.

If a potential difference of 12.0 V is required to produce a current of 3.0 A in a wire, the resistance of the wire is A. 4.0 W. B. 36 W. C. 0.25 W. D. 3.0 W.

A. 4.0 W.

The operation of the household circuit breaker depends on what property of an electrical current? A. The electrical current produces a magnetic field which opens the circuit breaker. B. The resistance in the wire melts the circuit breaker. C. The excessive amount of flowing electrons pushed the breaker open. D. The electrons in the wire repel the electrons in the breaker causing it to open.

A. The electrical current produces a magnetic field which opens the circuit breaker.

Why is the sky blue? A. The shorter wavelengths of blue and violet light are scattered more strongly than red and orange light. B. The light is reflected off the blue oceans. C. The longer wavelengths of red and orange light are scattered more strongly than blue and violet light. D. The sunlight is most intense in the blue-violet range.

A. The shorter wavelengths of blue and violet light are scattered more strongly than red and orange light.

The reason that someone can see a reflection in a mirror is that: A. a mirror is a smooth surface and light rays reflect from the surface of the mirror are parallel to each other in a definite direction. B. the mirror is a smooth surface and scatters light rays in all directions. C. the mirror absorbs and reflects light at different angles. D. the mirror is a smooth surface and absorbs and reflects light in all directions.

A. a mirror is a smooth surface and light rays reflect from the surface of the mirror are parallel to each other in a definite direction.

A common fundamental property of both electrons and protons is A. electric charge. B. size. C. length. D. volume.

A. electric charge.

The majority of the Sun's radiant energy is in the form of A. infrared radiation. B. visible light. C. ultraviolet radiation. D. gamma rays.

A. infrared radiation

A transformer in which the number of turns in the primary coil is greater than the number of turns in the secondary coil A. is called a step down transformer. B. is called a step up transformer. C. increases the secondary voltage. D. decreases the secondary current. E. maintains a constant output voltage .

A. is called a step down transformer.

The force between two charged particles A. is inversely proportional to the distance between them squared. B. is independent of the separation distance. C. is independent of the amount of charge on the particles. D. is always attractive never repulsive.

A. is inversely proportional to the distance between them squared.

An electric current is measured in units of A) volt. B) amp. C) watt. D) coulomb.

B) amp

An electric current is a(an) A) movement of electrons at near the speed of light. B) flow of charge. C) electrical equivalent of gravitational potential difference. D) measured in joules per coulomb.

B) flow of charge.

The Sun appears reddish as it sets because A) the Sun emits more energy at longer wavelengths at sunset. B) more of the shorter, bluer wavelengths are scattered away by the dust and haze. C) the Doppler shift lowers the frequency as a given spot on Earth rotates away from the Sun. D) more of the longer, redder wavelengths are scattered by the atmosphere.

B) more of the shorter, bluer wavelengths are scattered away by the dust and haze.

If you multiply amp Χ ohm, the answers will be in units of A) power B) potential C) current D) resistance

B) potential

The potential difference that is created by doing 1.00 joule of work in moving 1.00 coulomb of charge is defined to be A. 1.0 amp. B. 1.0 volt. C.1.0 watt. C.1.0 Newton.

B. 1.0 volt.

The frequency of a photon of red light that has a wavelength of 680 nm is A. 4.41 x 1014 m/s. B. 4.41 x 1014 Hz. C. 2.27 x 10-15 Hz. D. 6.80 x 10-15 Hz.

B. 4.41 x 1014 Hz.

What property of light do you have to keep in mind while looking at fish in a lake or stream? A. The speed of light does not change between one medium to another. B. Light bends when it hits the air to water interface. The fish that you spotted is not where you think it is. C. Water is transparent so you can see the fish's actual location. D. The fish emits blackbody radiation.

B. Light bends when it hits the air to water interface. The fish that you spotted is not

4) A conductor is a material which has electrons that are free to move. Which of the following is a conductor? A. Glass windows B. Silver spoon C. Diamond (Carbon) D. Rubber tire E. Only B & C

B. Silver spoon

Which of the following has the highest energy (i.e. highest frequency)? A. Infrared B. X-ray C. Visible light D. Microwave E. Ultraviolet

B. X-ray

Electric power is A. current divided by voltage. B. current times voltage. C. voltage divided by current. D. charge divided by time.

B. current times voltage.

Our eyes are most sensitive to sunlight with a frequency that is A. near the blue end of the visible region. B. near the yellow-green region of the visible spectrum. C. near the red-orange region of the visible region. D. ultraviolet.

B. near the yellow-green region of the visible spectrum.

One theory as to the cause of Earth's magnetic field is A. the eruption of lava containing ferromagnesians. B. the flowing of liquid iron and nickel within the core as Earth rotates. C. the accumulation of magnetite at the poles. D. a combination of all of the above.

B. the flowing of liquid iron and nickel within the core as Earth rotates.

If angle A is 60o, what does angle C measure? A) 60o B) 90o C) 30o D) roughly 25o (look at picture)

C) 30o

Polarizing sunglasses are useful because they are able to A) use the critical angle to block light. B) reflect glare. C) absorb reflected light, which is polarized. D) refract reflected light, which causes glare.

C) absorb reflected light, which is polarized.

We explain light today A) mostly with particle models. B) mostly as a wave phenomenon. C) as having both wave and particle characteristics. D) as something completely unknown.

C) as having both wave and particle characteristics.

The unit of electric charge is called a(n) A) electron. B) ampere. C) coulomb. D) ohm.

C) coulomb

An electric field A) has strength, but not direction. B) is present only around stationary electric charges. C) is always present around an electron. D) cannot exist unless a magnetic field is also present.

C) is always present around an electron.

The natural magnetic field surrounding Earth A) is produced by an excess of stationary electric charges. B) is produced by a deficiency of stationary electric charges. C) is produced by moving charges in Earth's core. D) attracts or repels stationary electric charges.

C) is produced by moving charges in Earth's core.

The index of refraction for flint glass is 1.5. This means that A) light travels faster in this substance than it does in vacuum. B) the wavelength of light passing through glass is 1.5× longer as it is in vacuum. C) the speed of light is slower in this substance than it is in vacuum. D) a ray of light is refracted away from the normal as it passes from air into glass

C) the speed of light is slower in this substance than it is in vacuum.

Electric field lines are drawn A) toward the positive test charge. B) away from the positive test charge. C) to show the direction a test charge would move D) radiating outward like spokes on a wheel.

C) to show the direction a test charge would move

Phenomena such as diffraction and interference can be most easily explained in terms of the A) ray model of light. B) particle model of light. C) wave model of light. D) photoelectric effect.

C) wave model of light.

13) A typical air conditioner unit draws a current of 25 A with a voltage of 220V. If the air conditioner "runs" for 240 hours a month, what does it cost to run if the cost of 1 kWh is $0.10. A. $6 B. $24 C. $132 D. $220

C. $132

Two spheres each have an excess of 1014 electrons and are separated by 1.0 m. The magnitude of the repulsive force between them is A. 0 N. B. 0.23 N. C. 2.3 N D. 23 N.

C. 2.3 N

Which of the following is not luminous? A. Sun B. Campfire C. Moon D. Fluorescent light

C. Moon

Why do polarized sunglasses reduce glare (reflected light)? A. The reflected light is unpolarized. B. The reflected light is polarized in the same horizontal plane as the sunglasses. C. The reflected light is polarized in the horizontal plane and the glasses are polarized in the vertical plane. D. The reflected light is polarized in the vertical plane and the glasses are polarized in the horizontal plane.

C. The reflected light is polarized in the horizontal plane and the glasses are polarized in the vertical plane.

The incident angle of a light ray that travels from water to air and is refracted at 90o is called the A. reflected angle. B. angle of refraction. C. critical angle. D. normal angle.

C. critical angle.

When white light is passed through a prism at the correct angle, the colors of the rainbow are produced. This dispersion of light is due to the fact that A. the energy levels of each color is different. B. the light is polarized. C. each color of light has its own index of refraction. D. all of the above are correct.

C. each color of light has its own index of refraction.

1) In an experiment in the late 1800's, J. J. Thomson discovered that all matter contained negatively charged particles. These particles were named after the Greek word for amber. Today these sub-atomic particles are named A. protons. B. neutrons. C. electrons. D. quarks.

C. electrons.

A blue SUV appears blue because it A. refracts blue light in the 460 nm to 490 nm range. B. absorbs blue light in the 460 nm to 490 nm range. C. reflects blue light in the 460 nm to 490 nm range. D. disperses blue light.

C. reflects blue light in the 460 nm to 490 nm range.

17) The magnitude of an induced voltage does NOT depend on A. the number of wire loops passing through the magnetic field. B. the strength of the magnetic field. C. the resistance of the wire. D. the rate at which magnetic field lines pass through the wire.

C. the resistance of the wire.

The resistance of a wire depends on A) the length of the wire. B) the cross-sectional area of the wire. C) the temperature of the wire. D) All of the answers are correct.

D) All of the answers are correct.

Total internal reflection A) occurs when light strikes an interface at greater than the critical angle. B) accounts for the brilliance of cut diamonds. C) allows light to travel in a curved path inside an optic fiber. D) All of the answers are correct.

D) All of the answers are correct.

The frequency of light is A) directly proportional to its wavelength. B) inversely proportional to the velocity. C) independent of the temperature of the source. D) None of the answers is correct.

D) None of the answers is correct.

The unit of electric potential difference between two points is A) an ampere. B) a coulomb. C) a joule. D) a volt.

D) a volt.

What is it that travels through an electric circuit at near the speed of light? A) electrons. B) protons C) a potential difference D) an electric field

D) an electric field

Max Planck discovered that the blackbody radiation emitted by vibrating molecules A) was continuous, like a train of waves. B) was constant for all objects. C) varied greatly from one experiment to the next. D) appeared to come in multiples of certain fixed amounts.

D) appeared to come in multiples of certain fixed amounts.

Ohm's law states A) a relationship between voltage, current, and charge. B) that less current flows when a higher voltage is applied. C) that for constant voltage, a greater resistance means more current will flow. D) that the current in a circuit increases if the potential difference increases.

D) that the current in a circuit increases if the potential difference increases.

The photoelectric effect could not be adequately explained with a wave model of light because A) the energy of the electrons ejected from a metal varied directly with the intensity. B) the number of electrons ejected from a metal depended upon the intensity. C) the number of electrons ejected from a metal depended upon the wavelength. D) the energy of the ejected electrons did not depend upon the intensity.

D) the energy of the ejected electrons did not depend upon the intensity.

Electric power is measured in units of A) volts B) amps. C) ohms D) watts

D) watts

In an ideal transformer, the primary voltage is 120 V and the primary current is 2.0A. If the output voltage is 1200 V, the output current will be A. 20 A. B. 2.0 A. C. 5.0 A D. 0.2 A

D. 0.2 A

13) A ray of orange light has a frequency of 4.9 x 1014 Hz. The corresponding wavelength of this light is A. 490 nm. B. 160 nm. C. 300 nm. D. 612 nm.

D. 612 nm.

Which of the following are misconceptions concerning electric current? A. The electrons move at nearly the speed of light through a wire. B. Electrons are pushed out of the wire as more enter the wire. C. The flow of electrons is like the flow of water in a pipe. D. All of the above are misconceptions.

D. All of the above are misconceptions.

Which of the following properties of light cannot be described by using the wave model of light? A. Interference B. Diffraction C. Polarization D. Photoelectric effect

D. Photoelectric effect

Light that interacts with matter can be A. reflected. B. absorbed. C. transmitted. D. any combination of the above.

D. any combination of the above.

An electrostatic charge, commonly called static electricity, can be produced A. by transferring electrons through friction. B. by transferring electrons direct contact between the objects. C. by induction which redistributed electrons through a material. D. as a result of any of the above.

D. as a result of any of the above.

Which of the following is an incandescent light source? A. laser B. moon C. fluorescent light D. candle

D. candle

The flow of charge is defined as A. potential difference. B. power. C. energy. D. current.

D. current.

When viewed from a stationary platform, an object moving at speeds approaching the speed of light would, according to the Special Theory of Relativity, A. be shorter than when it was not moving. B. have an increased mass. C. find that time has slowed down. D. find that all of the above are true.

D. find that all of the above are true.

In 1820, Hans Oersted discovered that electrical currents produce magnetic fields when A. he moved a permanent magnet over a compass. B. he moved a copper wire over a magnet. C. he observed a magnet moving a copper wire. D. he found that a wire carrying a current deflected the needle of a magnetic compass.

D. he found that a wire carrying a current deflected the needle of a magnetic compass.

The ratio of the speed of light in a vacuum to the speed of light in a medium A. is called the critical ratio. B. is always less than 1. C. is always equal to 1 since the speed of light is a constant. D. is called the index of refraction.

D. is called the index of refraction.

What is the photoelectric effect? A. Electrons are emitted when specific materials are exposed to light. B. Energy of a light wave occurs in discrete amounts of energy called quanta. C. Einstein defined the quanta as photons. D. Light is a stream of moving particles called photons. E. All above describe the photoelectric effect.

E. All above describe the photoelectric effect.

Can you name everyday things that make life easier for us because of electromagnets? A. electric meters B. thermostats C. mechanical switches on VCRs and doorbells D. electric motors E. All of the above

E. All of the above

Electrical charge A. is measured in units of coulombs. B. of an electron is 1.60 x 10-19 coulombs. C. of an electron cannot be divided. D. of 1 coulomb equals the charge of 6.24 x 1018 protons. E. is defined by all of the above.

E. is defined by all of the above.

An object becomes positively charged by gaining protons. T/F

F

The electrical force is much weaker than the force of gravity. t/f

F

The angle of incidence is equal to the angle of refraction.

False

a fluorescent light source emits light as a result of high temperature. T/F

False

The north end of a suspended magnet will point to Earth's magnetic north pole. t/f

T

The range of energies emitted by the sun is most intense near the yellow green wavelengths. T/F

True

which of the following objects does NOT emit visible light of its own?

a candle flame. the sun the moon a burning ember of coal answer: the moon

Magnetic field lines around a wire that is producing them ______. a) form closed loops b) cross and join with other lines c) form individual line segments

a) form closed loops

A(n) ______ measures electric currents by measuring the magnetic fields they produce. a) galvanometer b) transformer c) electronic relay d) solenoid

a) galvanometer

A solenoid is a ______ formed by loops of wire. a) bowl b) cylindrical coil c) cube

b) cylindrical coil

Many loops of wire formed into a cylindrical coil are called a(n) ______. a) electromagnet b) solenoid c) galvanometer d) battery

b) solenoid

Which numbered arrow is the refracted ray indicated by? A) 1. B) 2 C) 3 D) 4 (look at picture)

b: 2

If 1 is the incident ray, what is the angle of reflection? A) A. B) B C) C D) D (look at picture)

b: b

An electromagnet can be produced by passing a current ______. a) near a magnetic compass made of silver b) back and forth between two opposite static charges c) through a solid metal sphere d) through the wires of a solenoid

c) through a solid metal sphere

You are able to see non-luminous objects because light has undergone...

diffuse reflection refraction constructive interference a change in speed answer: diffuse reflection

an axle with many loops of wire on it rotating inside a magnetic field due to an outside form of mechanical energy is the basis setup of an..

electric generator

When a voltage is induced in a wire using a magnetic field by changing the field r by moving the wire, an induced current results. This interaction is called blank induction.

electromagnetic induction

when an electric stove element is hot enough, it gives off a dull red glow. When it cools to the point that it no longer glows, it will...

emit only shorter wavelength energy emit the same wavelength as before, but with less energy. emit inly longer wavelength energy. stop emitting energy altogether. answer: emit only longer wavelength energy

Electrons move from the power plant to homes in an alternating current. t/f

f

If one cuts a current carrying wire, the flow of electricity will spill out into the air. t/f

f

Interference is a property of light most easily explained by the particle model. T/F

false

Charge moving through a wire produces a magnetic field around the wire. t/f

t

If you double the distance between two charged objects, you reduce the electrical force by a factor of four. T/F

t

The attractive force between two unlike charges has the same strength as the repulsive force between two like charges. T/f

t

The volt is a measure of the difference in electrical potential energy between two points. t/f

t

The change in the direction of light as it passes through the boundary between two media is called refraction.

true

The slower light through a given substance, the greater the index of refraction.

true

Ultraviolet light waves carry more energy than infrared light waves. T/F

true