DC - Midterm

Alternating current is described as _____. a. omnidirectional b. unidirectional c. bidirectional

Bidirectional

What is the term for an amount of charge equal to 6.25 x 1018 electrons? a. coulomb b. ampere c. volt d. watt

coulomb

The resistor color code's

0-black 1-brown 2-red 3-orange 4-yellow 5-green 6-blue 7-violet 8-gray 9-white 5%-gold 10%-silver 20%-no band

The _____ is equal to one coulomb per second. a. ohm b. watt c. volt d. ampere

Ampere

Direct current is described as _____. a. bidirectional b. omnidirectional c. unidirectional

Unidirectional

The three Ohm's Law equations

V= IR I= V/R R= V/I

If a thundercloud has a positive charge, the current in the lightning bolt will flow from the _____. a. ground to the cloud b. cloud to the ground

ground to cloud

The neutral conductor is also referred to as the _____ conductor. a. hot b. short c. grounded d. safety

grounded

A _____ resistor is made by applying a film of metal to a ceramic rod in a vacuum. a. wire-wound b. metal film c. composition carbon d. metal glaze

metal film

A _____ resistor operates by moving the wiper arm with a screw of some number of turns. a. wire-wound b. pot c. multiturn variable d. rheostat

multiturn variable

The precipitator uses a high-voltage DC power supply to provide a set of wires with a positive charge and a set of plates with a _____ charge. a. positive b. negative

negative

The part of an atom that has no charge is the _____. a. quark b. electron c. neutron d. proton

neutron

Bringing a charged test object near the ball of a charged electroscope causes the leaves to move closer together. This indicates that the test object charge is the _____ polarity as the electroscope charge. a. opposite b. same

opposite

The valence shell of an atom is the _____ shell. a. outer b. inner c. bottom d. middle

outer

Valence electrons are contained in the _____ shell. a. inner b. bottom c. middle d. outer

outer

The measure of a material's ability to be magnetized is called _____. a. permeability b. reluctance c. saturation d. residual magnetism

permeability

A variable resistor is also called a _____. a. wire wound resistor b. potentiometer c. metal film resistor d. multiturn resistor

potentiometer

A variable resistor with three terminals is called a _____. a. multiturn resistor b. wire wound resistor c. potentiometer d. rheostat

potentiometer

The part of an atom that has a positive charge is the _____. a. electron b. neutron c. quark d. proton

proton

The atomic number of an element is the number of _____ in the nucleus. a. quarks b. neutrons c. protons d. electrons

protons

The measure of a material's resistance to magnetism is _____. a. permeability b. residual magnetism c. reluctance d. saturation

reluctance

Opposition to current flow is called _____. a. amperage b. divergence c. resistance d. voltage

resistance

A variable resistor with two terminals is called a _____. a. wire wound resistor b. multiturn resistor c. rheostat d. potentiometer

rheostat

When a magnetic materials molecules are all lined up, and increases in current flow no longer cause increases in magnetic field strength, the material has reached _____. a. reluctance b. saturation c. residual magnetism d. permeability

saturation

A(n) _____ circuit generally occurs when the conductors leading from and back to the power source become connected. a. closed b. open c. short d. grounded

short

In a(n) _____ circuit, there is very little resistance and a large amount of current flows. a. short b. openx c. long d. closed

short

The north magnetic pole of a compass needle is attracted to the _____ magnetic pole of the earth. a. south b. north c. east d. west

south

The static charge sometimes used during spray painting is called a(n) _____ static charge. a. useful b. nuisance

useful

Electrical current is the flow of _____. a. quarks b. protons c. neutrons d. electrons

electrons

Resistors that only have one ohmic value are called _____ resistors. a. composition b. fixed c. metal film d. variable

fixed

The current flow that occurs within a lightning bolt flows _____. a. from positive to negative b. in both directions c. from negative to positive

from negative to positive

The velocity of AC through a conductor is _____ the speed of light because magnetic fields travel more slowly in material dielectrics than they do through free air. a. greater than b. equal to c. less than

less than

Man-made permanent magnets retain their magnetism _____ than natural magnets. a. longer b. less

longer

If you walk across a carpet, touch a doorknob and get a shock, the shock was the result of a(n) _____ static charge. a. useful b. nuisance

nuisance

A _____ resistor is made by winding a piece of resistive wire around a ceramic core. a. metal film b. metal glaze c. wire-wound d. carbon film

wire-wound

_____ is also referred to as electromotive force (EMF). a. Amperage b. Ohmage c. Wattage d. Voltage

Voltage

_____ were used in vacuum-tube circuits many years ago and are still used today in applications involving field-effect transistors (FETs) and multirange voltmeter circuits. a. Current dividers b. Voltage dividers c. Current multipliers d. Voltage multipliers

Voltage dividers

A precipitator is a type of _____. a. power supply b. small wire c. air filter d. lightning rod

air filter

The strength of an electromagnet is primarily proportional to its _____. a. core resistance b. length c. diameter d. ampere-turns

ampere-turns

The lightning protection device that does not connect directly to the object to be protected is called the lightning _____. a. umbrella b. rod c. arrestor d. catcher

arrestor

An element cannot be chemically subdivided into other elements. The smallest part of an element is a(n) _____. a. electron b. atom c. proton d. neutron

atom

A basic law of magnetism states that unlike poles _____ and like poles _____. a. attract, repel b. repel, attract

attract, repel

Objects charged with different type of charges will draw toward each other. This is referred to as _____. a. repulsion b. attraction

attraction.

A conductor is made from a material that contains between _____ valence electrons. a. one and three b. two and four c. three and five d. four and six

1 & 3

The four factors used to determine the resistance of a material

1. The type of material 2. The length of the material 3. The cross-sectional area of the material 4. The temperature

The six parts of most complete electrical circuits and an example for each

1.Source-battery 2.Load-lamp 3.Control Device-switch 4.Protection Device-fuse 5.Conductor-copper 6.Insulator-rubber

Electrons can form spin patterns that _____ the magnetic field of the material. a. add b. cancel

cancel

A _____ resistor is made by applying a film of carbon to a ceramic rod. a. wire-wound b. carbon film c. metal glaze d. metal film

carbon film

The Greeks were the first to discover electricity about _____ years ago. a. 100 b. 1000 c. 2500 d. 5000

2500

Current that flows in both directions is referred to as _____ current. a. direct b. alternating

AC - Alternating

The force of electrostatic attraction or repulsion is directly proportional to the product of the two charges and inversely proportional to the square of the distance between them. This is _____ law. a. Coulomb's b. Ohm's c. Ampere's d. Volt's

coulomb's

Current that flows in only one direction is referred to as _____ current. a. direct b. alternating

DC - Direct

The angular difference between true north and magnetic north is known as the angle of _____. a. polarity b. magnetism c. retribution d. declination

declination

If an object is placed in the field of an strong electromagnet connected to an AC line, the object will be _____. a. magnetized b. demagnetized

demagnetized

The regions formed in the molecular structure of magnetic metals is sometimes called magnetic _____. a. domains b. atoms c. quarks d. spins

domains

Insulators are the only materials that can hold _____ stationary. a. electrons b. atoms

electrons

zz

zz

An insulator is a material containing _____ valence electrons. a. one or two b. three or four c. five or six d. seven or eight

7 or 8

A _____ resistor is made from a compound of carbon graphite and resin bonding material. a. metal film b. composition carbon c. metal glaze d. wire-wound

composition carbon

A _____ resistor is made by combining metal with glass and then applying it to a ceramic base as a thick film. a. metal glaze b. metal film c. carbon film d. wire-wound

metal glaze

A resistor has color bands of brown, black, red, and silver. What is the resistance and tolerance of the resistor? a. 100 W, 10% b. 1000 W, 10% c. 1000 W, 5% d. 100 W, 5%

1000 W, 10%

An electric circuit has a resistance of 20 W. The current is measured to be 6 A. How many volts are applied to the circuit? a. 3 1/3 b. 14 c. 26 d. 120

120

A toaster is listed as 1560 W. When it is plugged into a 120 V circuit and starts to make toast, how many amperes will it draw? a. 13 b. 1440 c. 1680 d.187,200

13

A resistor has color bands of red, violet, brown, and gold. What is the resistance and tolerance of the resistor? a. 270 W, 10% b. 270 W, 5% c. 2700 W, 5% d. 2700 W, 10%

270 W, 5%

A semiconductor contains _____ valence electrons. a. three b. four c. five d. seven

4

An electrical device is listed as 3,000 watts. Approximately how many horsepower is this? a. 1/4 b. 1/6 c. 4 d. 6

4

The statement "in a DC circuit, the current is directly proportional to voltage and inversely proportional to resistance" is know as _____ law. a. Coulomb's b. Ampere's c. Ohm's d. Volt's

Ohm's

The three power equations

P= IV P= I2R P= V2/R

Matter can exist in two states: solid and liquid

True

Matter has mass and occupies space.

True

Wire-wound resistors are often used because they are able to operate at _____ power levels than other resistors. a. more efficient b. lower c. the same d. higher

higher

An opposition to current flow that occurs in alternating current circuits is called _____. a. voltage b. current c. impedance d. resistance

impedance

A magnet that produces a magnetic field as long as current is flowing is called a(n) _____ magnet. a. temporary magnet b. electromagnet c. domain magnet d. permanent magnet

electromagnet

Magnetism can be explained in terms of _____ spin patterns. a. quark b. neutron c. proton d. electron

electron

The part of an atom that has a negative charge is the _____. a. proton b. quark c. electron d. neutron

electron

The three principle parts of an atom are the _____. a. neutron, quark, and electron b. electron, proton, and quark c. neutron, positron, and electron d. electron, neutron, and proton

electron, proton & neutron

Magnetic lines of force are called _____. a. bands b. flux c. reluctance d. spin

flux

In the English system of measure, magnetic strength is measured in a term called _____. a. permeability b. residual magnetism c. flux density d. reluctance

flux density

Electrostatic charges occur on _____. a. conductors b. insulators

insulators

The three substances that form natural magnets are _____. a. copper, nickel, and boron b. iron, boron, and cobalt c. copper, iron, and cobalt d. iron, nickel, and cobalt

iron, nickel, and cobalt

A static electric charge is an electric charge which _____ moving. a. is not b. is

is not

To locate the north pole of an electromagnet, use the _____ hand rule. a. left b. right

left

The most common method of producing electricity is _____. a. light b. magnetism c. friction d. chemicals

magnetism

Lodestone is a name for a naturally occurring magnetic material that is also called _____. a. magnetism b. copper c. lead d. magnetite

magnetite

In the English system, the total force producing a magnetic field is the _____. a. flux density b. reluctance c. magnetomotive force d. permeability

magnetomotive force

The nucleus of an atom contains _____. a. electrons and quarks b. neutrons and protons c. electrons and protons d. neutrons and quarks

neutrons and protons

The unit of resistance to current flow is the _____. a. ampere b. volt c. watt d. ohm

ohm

The law of charges states that like charges _____ and opposite charges _____. a. repel, attract b. attract, attract c. repel, repel d. attract, repel

repel; attract

Objects charged with the same type of charge will push each other away. This is referred to as _____. a. attraction b. repulsion

repulsion

When an object protected by a lightning _____ is struck by a lightning bolt, it will bleed the lightning discharge to ground before the protected object can be harmed. a. rod b. arrestor c. umbrella d. catcher

rod

The semiconductor material used as a coating on copy machine drums is _____. a. silicon b. germanium c. aluminum d. selenium

selenium

Selenium is a(n) _____. a. semiconductor b. conductor c. insulator

semiconductor

The _____ of a resistor indicates the plus and minus limits of a resistor's ohmic value. a. tolerance b. coefficient c. wattage d. resistance

tolerance

What does the fourth band of color on a resistor indicate? a. number values b. tolerance c. multiplier d. divider

tolerance

The unit of electrical "pressure" that causes current to flow is called the _____. a. volt b. watt c. ampere d. ohm

volt

An electric motor is running on 120 V. The current is measured to be 2 A. How many ohms of resistance is the motor? a. 60 b. 118 c. 122 d. 240

60

_____ do not require any power of force to maintain their field. a. Permanent magnets b. Temporary magnets c. Electromagnets d. Domain magnets

Permanent magnets

Identify electrical schematic symbols

Switches: SPST, SPDT, DPST, DPDT Momentary types N.O and N.C. Resistors: Fixed Value, Tapped, Variable, Potentiometer and Rheostat Other symbols: ground, fuse, lamp, battery, and cell.

A complete circuit is often referred to as a(n) _____ circuit. a. closed b. shorted c. grounded d. open

closed

The static charge that accumulates on clothes in a dryer is a(n) _____ charge. a. nuisance b. useful

nuisance

The amount of magnetism left in a material after the magnetizing force has stopped is called _____. a. saturation b. permeability c. residual magnetism d. reluctance

residual magnetism

An electrical circuit has a voltage of 50 V and a resistance of 5 W. What is the value of current? a. 10 A b. 45 A c. 55 A d. 250 A

10 A

A resistor whose values can be varied over a range of values is called a _____ resistor. a. fixed b. carbon c. wire wound d. variable

variable

The _____ is used to measure electrical power being used in a circuit. a. watt b. ampere c. ohm d. volt

watt

If a circuit is open, current _____ flow. a. will not b. will

will not