Deck 7: Electricity

Question 1

An object that has zero resistance is a semiconductor.

Answer 1

False

Question 2

An atom with fewer electrons than protons is a negative ion.

Answer 2

False

Question 3

Current is the opposition to the flow of charge.

Answer 3

False

Question 4

Two charged bodies separated by a distance d exert a repulsive electrical force on each other. The signs of the charges on the two bodies are + and -.

Question 5

The resistance of a conducting material depends on its composition, length, diameter, and temperature.

Question 6

The SI unit of electric charge is e , the charge on the electron.

Question 7

Solids that are good conductors of heat tend also to be good conductors of electricity.

Question 8

Larger batteries have higher output voltages.

Question 9

Electrons are negatively charged.

Question 10

Semiconductor technology has been the basis for many new electronic devices.

Question 11

If the length of a wire increases, its resistance decreases.

Question 12

Current is the rate of flow of electric charge.

Question 13

Superconductivity is lost when a certain critical temperature is exceeded.

Question 14

The resistance of a wire does not change when its temperature changes.

Question 15

Voltage is a measure of the energy per unit charge supplied by a battery.

Question 16

Voltage can also be called potential.

Question 17

Voltage is the force on a charged object divided by the charge on the object.

Question 18

Two charged bodies separated by a distance d exert an electrical force on each other. The distance d is doubled. The electrical force on each body is now 1/2 of the original force.

Question 19

All three types of particles found in atoms are electrically charged.

Question 20

If the diameter of a wire increases, its resistance decreases.

Question 21

A light bulb used in a slide projector draws a current of 6 amperes when operating on 120 volts.
The power consumed by the light bulb is 20 watts.

Question 22

A battery stores electric charge in the same way that a bottle stores water.

Question 23

A light bulb designed for use with AC would still work if hooked up to DC of the proper voltage.

Question 24

An alternate equation for power in an electric circuit is P = IR .

Question 25

If the current drawn from a 12-volt car battery is 100 amperes when it is short circuited with a wire, the resistance of the wire is 0.12 ohms.

Question 26

A light bulb used in a slide projector draws a current of 6 amperes when operating on 120 volts.
If two slide projectors are connected in series across the same 120-volt source, the current drawn from the source remains at 6 amperes.

Question 27

In a circuit connected to a battery, the current flows from negative pole toward the positive pole of the battery.

Question 28

A light bulb used in a slide projector draws a current of 6 amperes when operating on 120 volts.
The resistance of the light bulb is 20 ohms.

Question 29

The energy used by a 100-watt light bulb in 1 hour is 100 kilowatt-hours.

Question 30

A heater is rated at 1200 watts for a 120-volt source.
If two heaters are connected in parallel across the 120-volt source, the current drawn from the source is 10 amperes.

Question 31

A heater is rated at 1200 watts for a 120-volt source.
The resistance of the heater is 10 ohms.

Question 32

In a parallel circuit, the size of the current flowing through each device may be different.

Question 33

A heater is rated at 1200 watts for a 120-volt source.
If two heaters are connected in parallel across the 120-volt source, the total power drawn from the source increases to 2400 watts.

Question 34

If an electric toaster operating on 120 volts draws a current of 6 amperes, the resistance of the toaster is 20 ohms.

Question 35

A light bulb used in a slide projector draws a current of 6 amperes when operating on 120 volts.
If two slide projectors are connected in parallel across the same 120-volt source, the current drawn from the source remains at 6 amperes.

Question 36

An electrostatic precipitator uses an electric field to remove smoke from the air.

Question 37

In a parallel circuit with three resistors all the same size, the current flow though each leg of the circuit will be equal.

Question 38

A battery operating a large flashlight produces a current of 2 amperes in a light bulb that has a resistance of 4 ohms. The voltage of the battery is 2 volts.

Question 39

The energy used by a 100-watt light bulb in 1 hour is 360,000 joules

Question 40

A heater is rated at 1200 watts for a 120-volt source.
The current drawn by the heater is 10 amperes.

Question 41

What is meant by 'like charges?'

A) charges that are both positive
B) equal amounts of charge
C) charges that are both negative
D) A and C

Question 42

A positive ion is formed when

A) a neutral atom gains an electron.
B) a neutral atom loses an electron.
C) a negative ion loses an electron.
D) all of the above

Question 43

An atom with fewer electrons than protons is

A) a semiconductor.
B) a superconductor.
C) a positive ion.
D) a negative ion.
E) none of the above.

Question 44

A car headlight and an interior dome light use the same voltage, but the headlight consumes much more power because

A) its resistance is lower.
B) the current in it is larger.
C) it uses energy faster.
D) all of the above

Question 45

Why do we use fuses?

A) to eliminate shock hazards
B) to prevent fires
C) to save on the cost of electricity
D) to store charge

Question 46

What is meant by 'net charge?'

A) the total amount of positive charge on an object
B) the total amount of negative charge on an object
C) the total amount of neutral charge on an object
D) A minus B

Question 47

A quantity that is measured in ohms is

A) voltage.
B) current.
C) resistance.
D) electric field.
E) critical temperature.

Question 48

In general, an insulator will have a low resistance to current flow.

Question 49

The SI unit of electric charge is

A) e , the charge on the electron.
B) the coulomb.
C) the ampere.
D) the ohm.
E) the volt.

Question 50

If three identical bulbs are connected in series across a 12-V battery, the voltage across each bulb will be

A) 12 V.
B) 4 V.
C) different.
D) none of the above.

Question 51

A quantity that measures the opposition to the flow of charge is

A) voltage.
B) current.
C) resistance.
D) electric field.
E) critical temperature.

Question 52

If three identical bulbs are connected in parallel across a 12-V battery, the voltage across each bulb will be

A) 12 V.
B) 4 V.
C) different.
D) none of the above.

Question 53

An electric current can consist of

A) positive ions flowing in a liquid.
B) negative ions flowing in a liquid.
C) electrons flowing in a wire.
D) all of the above.

Question 54

Superconductivity is lost when a certain ____is exceeded.

A) voltage
B) current
C) resistance
D) electric field
E) critical temperature

Question 55

The rate of flow of electric charge is

A) voltage.
B) current.
C) resistance.
D) electric field.
E) critical temperature.

Question 56

An object that has zero resistance is a

A) semiconductor.
B) superconductor.
C) diode.
D) transistor.
E) positive ion.

Question 57

If you think of a battery as an electric charge 'pump,' the battery voltage is analogous to

A) rate of fluid flow.
B) pressure.
C) flow velocity.
D) water.
E) none of the above.

Question 58

Suppose current is flowing in a wire from right to left. Which way do the electrons in the wire move?

A) right to left
B) left to right
C) in circles
D) It is impossible to tell.

Question 59

Voltage can also be called

A) potential.
B) pressure.
C) work.
D) energy.
E) none of the above.

Question 60

The energy per unit charge supplied by a battery is its

A) voltage.
B) current.
C) resistance.
D) electric field.
E) critical temperature.

Question 61

The light bulbs in this circuit are connected in

A) parallel.
B) series.
C) neither parallel nor series.
D) a short circuit.

Question 62

The kilowatt-hour is a unit of

A) power.
B) energy.
C) voltage.
D) current.

Question 63

The force on a charged object divided by the charge on the object is

A) voltage.
B) current.
C) resistance.
D) electric field.
E) critical temperature.

Question 64

Electrons are

A) positively charged.
B) negatively charged.
C) uncharged.
D) variably charged.

Question 65

The electric field shown is produced by a single point charge at the center of the picture. What force will a negative charge placed at location C feel?

A) zero
B) a force up and to the left
C) a force up and to the right
D) a force down and to the left
E) a force down and to the right

Question 66

The resistance of a conducting material depends on its

A) composition.
B) length.
C) diameter.
D) temperature.
E) all of the above

Question 67

If the length of a wire increases, its resistance

A) increases.
B) decreases.
C) does not change.
D) will increase or decrease depending on the composition.
E) will change in a way that can not be determined.

Question 68

The electric field shown is produced by a single point charge at the center of the picture. What type of charge produces the electric field shown?

A) positive
B) negative
C) neutral
D) impossible to tell

Question 69

An electric toaster operating on 120 volts draws a current of 6 amperes. The resistance of the toaster is

A) 0.05 ohms.
B) 20 ohms.
C) 720 ohms.
D) none of the above.

Question 70

The electric field shown is produced by a single point charge at the center of the picture. If a new negative point charge is placed at location B directly above the one pictured, the force on it will

A) be zero.
B) push it upward.
C) push it downward.
D) be in an unknown direction.

Question 71

Two charged bodies separated by a distance d exert an electrical force on each other. The distance d is doubled. The electrical force on each body now

A) decreases by 1/4.
B) decreases by 1/2.
C) stays the same.
D) increases by 2 times.
E) increases by 4 times.

Question 72

When a 12-volt car battery is short circuited with a wire, the current drawn from the battery is 100 amperes. The resistance of the wire is

A) zero.
B) 0.12 ohms.
C) 100/12 = 8.33 ohms.
D) 1200 ohms.
E) none of the above.

Question 73

If the temperature of a wire increases, its resistance

A) increases.
B) decreases.
C) does not change.
D) will increase or decrease depending on the composition.
E) will change in a way that can not be determined.

Question 74

If the diameter of a wire increases, its resistance

A) increases.
B) decreases.
C) does not change.
D) will increase or decrease depending on the composition.
E) will change in a way that can not be determined.

Question 75

What is the usual symbol used to represent an amount of charge?

A) C
B) q
C) e
D) none of the above

Question 76

When we say charges are 'positive' or 'negative' we are speaking of

A) two intrinsically different types of charge found in nature.
B) an excess vs. a deficiency of charge.
C) charges existing vs. not existing.
D) none of the above.

Question 77

A battery operating a large flashlight produces a current of 2 amperes in a light bulb that has a resistance of 4 ohms. The voltage of the battery is

A) 0.5 volts.
B) 2 volts.
C) 8 volts.
D) none of the above.

Question 78

If I short out a D cell and draw a current of 7 A for 5 s, how many coulombs of charge move through the circuit?

A) 7 C
B) 5 C
C) 7/5 C
D) 35 C

Question 79

The electric field shown is produced by a single point charge at the center of the picture. If a new positive point charge is placed at location A directly to the right of the one pictured, the force on it will

A) be zero.
B) push it to the right.
C) push it to the left.
D) be in an unknown direction.

Question 80

Two charged bodies separated by a distance d exert an electrical force on each other. The charge on one of the bodies is doubled. The electrical forces on each body now

A) double.
B) decrease by 1/2.
C) stay the same.
D) differ-the force on the other body doubles, but the force on the body whose charge was changed stays the same as before.
E) increase by a factor of four.