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Let's Review Regents: Physics—Physical Setting

Miriam A. Lazar

Chapter 9

Electric Current and Circuits - all with Video Answers

Educators

Chapter Questions

01:22

Problem 1

An ampere can be defined as 1
(A) $\mathrm{C} / \mathrm{s}$
(B) $\Omega / \mathrm{V}$
(C) $\mathrm{J} / \mathrm{C}$
(D) $\mathrm{N} / \mathrm{C}$

Rachel B.
Rachel B.
Numerade Educator
00:54

Problem 2

Electrical conductivity in liquid solutions depends on the presence of free
(A) neutrons
(B) protons
(C) molecules
(D) ions

Rachel B.
Rachel B.
Numerade Educator
01:53

Problem 3

As the temperature of a coil of copper wire increases, its electrical resistance
(A) decreases
(B) increases
(C) remains the same

Rachel B.
Rachel B.
Numerade Educator
02:42

Problem 4

If the cross-sectional area of a metallic conductor is halved and the length of the conductor is doubled, the resistance of the conductor will be
(A) halved
(B) doubled
(C) unchanged
(D) quadrupled

Rachel B.
Rachel B.
Numerade Educator
02:07

Problem 5

Which segment of copper wire has the highest resistance at room temperature?
(A) $1.0 \mathrm{~m}$ length, $1.0 \times 10^{-6} \mathrm{~m}^{2}$ cross-sectional area
(B) $2.0 \mathrm{~m}$ length, $1.0 \times 10^{-6} \mathrm{~m}^{2}$ cross-sectional area
(C) $1.0 \mathrm{~m}$ length, $3.0 \times 10^{-6} \mathrm{~m}^{2}$ cross-sectional area
(D) $2.0 \mathrm{~m}$ length, $3.0 \times 10^{-6} \mathrm{~m}^{2}$ cross-sectional area

Rachel B.
Rachel B.
Numerade Educator
01:18

Problem 6

The ratio of the potential difference across a conductor to the current in the conductor is called
(A) conductivity
(B) resistance
(C) charge
(D) power

Rachel B.
Rachel B.
Numerade Educator
01:16

Problem 7

Most metals are good electrical conductors because
(A) their molecules are close together
(B) they have high melting points
(C) they have many intermolecular spaces through which the current can flow
(D) they have a large number of free electrons

Rachel B.
Rachel B.
Numerade Educator
03:16

Problem 8

Which graph represents a circuit element at constant temperature that obeys Ohm's law?

Rachel B.
Rachel B.
Numerade Educator
03:10

Problem 9

Which graph best represents the relationship between the resistance $(R)$ of a solid conductor of constant cross section and its length $(L)$ ?

Rachel B.
Rachel B.
Numerade Educator
01:23

Problem 10

The resistance of a wire at constant temperature depends on the wire's
(A) length, only
(B) type of metal, only
(C) length and cross-sectional area, only
(D) length, cross-sectional area, and type of metal

Rachel B.
Rachel B.
Numerade Educator
02:12

Problem 11

The current in a circuit is supplied by a generator. If the resistance in the circuit is increased, the force required to keep the generator turning at the same speed is
(A) decreased
(B) increased
(C) the same

Rachel B.
Rachel B.
Numerade Educator
01:02

Problem 12

The ratio of the potential difference across a conductor to the current in the conductor is called
(A) energy
(B) charge
(C) resistance
(D) power

Rachel B.
Rachel B.
Numerade Educator
02:19

Problem 13

The graph below shows how the voltage and current are related in a simple electric circuit.
For any point on the line, what does the ratio of $V$ to $I$ represent?
(A) work, in joules
(B) power, in watts
(C) resistance, in ohms
(D) charge, in coulombs

Rachel B.
Rachel B.
Numerade Educator
03:05

Problem 14

The graph below represents the relationship between potential difference and current for four different resistors. Which resistor has the greatest resistance?
(A) $A$
(B) $B$
(C) $C$
(D) $D$

Rachel B.
Rachel B.
Numerade Educator
02:24

Problem 15

Three ammeters are located near junction $P$ in a direct current circuit as shown in the diagram below. If ammeter $A_{1}$ reads 3 amperes and ammeter $A_{2}$ reads 4 amperes, what does ammeter $A_{3}$ read?
(A) $5 \mathrm{~A}$
(B) $7 \mathrm{~A}$
(C) $3 \mathrm{~A}$
(D) $8 \mathrm{~A}$

Rachel B.
Rachel B.
Numerade Educator
02:54

Problem 16

The diagram below represents currents flowing in branches of an electric circuit. What is the reading on ammeter $A$ ?
(A) $13 \mathrm{~A}$
(B) $17 \mathrm{~A}$
(C) $3 \mathrm{~A}$
(D) $33 \mathrm{~A}$

Rachel B.
Rachel B.
Numerade Educator
02:19

Problem 17

The diagram below represents currents flowing in branches of an electric circuit. What is the reading on ammeter $A$ ?
(A) $13 \mathrm{~A}$
(B) $17 \mathrm{~A}$
(C) $3 \mathrm{~A}$
(D) $33 \mathrm{~A}$

Rachel B.
Rachel B.
Numerade Educator
01:17

Problem 18

If the voltage across a 4 -ohm resistor is 12 volts, the current through the resistor is
(A) $0.33 \mathrm{~A}$
(B) $48 \mathrm{~A}$
(C) $3.0 \mathrm{~A}$
(D) $4.0 \mathrm{~A}$

Rachel B.
Rachel B.
Numerade Educator
01:14

Problem 19

A charge of $5.0$ coulombs moves through a circuit in o.5o second. How much current is flowing through the circuit?
(A) $2.5 \mathrm{~A}$
(B) $5.0 \mathrm{~A}$
(C) $7.0 \mathrm{~A}$
(D) $10 . \mathrm{A}$

Rachel B.
Rachel B.
Numerade Educator
01:56

Problem 20

What is the current in a conductor if $6.25 \times 10^{18}$ electrons pass a given point each second?
(A) $1 \mathrm{~A}$
(B) $1.6 \times 10^{-19} \mathrm{~A}$
(C) $2.6 \mathrm{~A}$
(D) $6.25 \times 10^{18} \mathrm{~A}$

Rachel B.
Rachel B.
Numerade Educator
01:04

Problem 21

A resistor carries a current of $0.10$ ampere when the potential difference across it is $5.0$ volts. The resistance of the resistor is
(A) $0.020 \Omega$
(B) $0.50 \Omega$
(C) $5.0 \Omega$
(D) $50 . \Omega$

Rachel B.
Rachel B.
Numerade Educator
00:55

Problem 22

If the potential difference across a 12-ohm resistor is 6 volts, the current through the resistor is
(A) $0.33 \mathrm{~A}$
(B) $0.50 \mathrm{~A}$
(C) $3.0 \mathrm{~A}$
(D) $4.0 \mathrm{~A}$

Rachel B.
Rachel B.
Numerade Educator
02:10

Problem 23

Three resistors, 4 ohms, 6 ohms, and 8 ohms, are connected in parallel in an electric circuit. The equivalent resistance of the circuit is
(A) less than $4 \Omega$
(B) between $4 \Omega$ and $8 \Omega$
(C) between $10 . \Omega$ and $18 \Omega$
(D) $18 \Omega$

Rachel B.
Rachel B.
Numerade Educator
03:10

Problem 24

Which combination of current and electromotive force would use energy at the greatest rate?
(A) $10 \mathrm{~A}$ at $110 \mathrm{~V}$
(B) $8 \mathrm{~A}$ at $110 \mathrm{~V}$
(C) $3 \mathrm{~A}$ at $220 \mathrm{~V}$
(D) $5 \mathrm{~A}$ at $110 \mathrm{~V}$

Rachel B.
Rachel B.
Numerade Educator
02:05

Problem 25

A 10-volt potential difference maintains a 2-ampere current in a resistor. The total energy expended by this resistor in 5 seconds is
(A) $10 \mathrm{~J}$
(B) $20 \mathrm{~J}$
(C) $50 \mathrm{~J}$
(D) $100 \mathrm{~J}$

Rachel B.
Rachel B.
Numerade Educator
02:27

Problem 26

What is the current in a normally operating 6o-watt, 120 -volt lamp?
(A) $1.0 \mathrm{~A}$
(B) $2.0 \mathrm{~A}$
(C) $0.50 \mathrm{~A}$
(D) $4.0 \mathrm{~A}$

Rachel B.
Rachel B.
Numerade Educator
01:20

Problem 27

How much electric energy will be used by a 115 -volt, 60 -watt light bulb in 1 minute?
(A) $60 \mathrm{~J}$
(B) $115 \mathrm{~J}$
(C) $3,600 \mathrm{~J}$
(D) $6,900 \mathrm{~J}$

Morgan Cheatham
Morgan Cheatham
Numerade Educator
02:14

Problem 28

If the current and the resistance of an electric circuit are each doubled, the power will
(A) remain the same
(B) be doubled
(C) be 8 times as large
(D) be quadrupled

Rachel B.
Rachel B.
Numerade Educator
01:08

Problem 29

An ampere-volt is a unit of
(A) work
(B) resistance
(C) energy
(D) power

Rachel B.
Rachel B.
Numerade Educator
02:21

Problem 30

An electric heater raises the temperature of a measured quantity of water. The water absorbs 6000 joules of energy from the heater in $30.0$ seconds. What is the minimum power supplied to the heater?
(A) $5.00 \times 10^{2} \mathrm{~W}$
(B) $2.00 \times 10^{2} \mathrm{~W}$
(C) $1.80 \times 10^{5} \mathrm{~W}$
(D) $2.00 \times 10^{3} \mathrm{~W}$

Rachel B.
Rachel B.
Numerade Educator
02:30

Problem 31

A circuit contains a rheostat (variable resistor) connected to a source of constant voltage. As the resistance of the rheostat increases, the power dissipated in the circuit
(A) decreases
(B) increases
(C) remains the same

Rachel B.
Rachel B.
Numerade Educator
02:31

Problem 32

In the circuit represented below, which switches must be closed to produce a current in conductor $A B$ ?
(A) 1 and 4
(B) 2 and 3
(C) 1,2, and 3
(D) 2,3, and 4

Rachel B.
Rachel B.
Numerade Educator
02:23

Problem 33

Note that question 33 has only three choices.
An electric circuit contains a variable resistor connected to a source of constant voltage. As the resistance of the variable resistor is increased, the power dissipated in the circuit.
(A) decreases
(B) increases
(C) remains the same

Rachel B.
Rachel B.
Numerade Educator
02:10

Problem 34

A circuit consists of a resistor and a battery. Increasing the voltage of the battery while keeping the temperature of the circuit constant would result in an increase in
(A) current, only
(B) resistance, only
(C) both current and resistance
(D) neither current nor resistance

Rachel B.
Rachel B.
Numerade Educator
01:24

Problem 35

Charge flowing at the rate of $2.50 \times 10^{16}$ elementary charges per second is equivalent to a current of
(A) $2.50 \times 10^{13} \mathrm{~A}$
(B) $6.25 \times 10^{5} \mathrm{~A}$
(C) $4.00 \times 10^{-3} \mathrm{~A}$
(D) $2.50 \times 10^{-3} \mathrm{~A}$

Nishant Kumar
Nishant Kumar
Numerade Educator
03:19

Problem 36

An electric drill operating at 120 . volts draws a current of $3.00$ amperes. What is the total amount of electrical energy used by the drill during $1.00$ minutes of operation?
(A) $2.16 \times 10^{4} \mathrm{~J}$
(B) $2.40 \times 10^{3} \mathrm{~J}$
(C) $3.60 \times 10^{2} \mathrm{~J}$
(D) $4.00 \times 10^{1} \mathrm{~J}$

Rachel B.
Rachel B.
Numerade Educator
03:33

Problem 37

A o.686-meter-long wire has a cross-sectional area of $8.23 \times 10^{-6}$ meter $^{2}$ and a resistance of $0.125 \mathrm{ohm}$ at $20^{\circ}$ Celsius. This wire should be made of
(A) aluminum
(B) copper
(C) nichrome
(D) tungsten

Rachel B.
Rachel B.
Numerade Educator
02:39

Problem 38

The algebraic sum of all the potential drops and applied voltages around a complete circuit is equal to zero. This is an application of the law of conservation of
(A) mass
(B) energy
(C) charge
(D) momentum

Rachel B.
Rachel B.
Numerade Educator
01:40

Problem 39

Base your answers to questions 39 through 43 on the information below.
An electric heater rated at 4800 watts is operated on 120 volts.
What is the resistance of the heater?
(A) $576,000 \Omega$
(B) $120 \Omega$
(C) $3.0 \Omega$
(D) $40 . \Omega$

Rachel B.
Rachel B.
Numerade Educator
01:49

Problem 40

How much energy is used by this heater in $10.0$ seconds?
(A) $1.15 \mathrm{~J}$
(B) $40 . \mathrm{J}$
(C) $4.8 \times 10^{3} \mathrm{~J}$
(D) $4.8 \times 10^{4} \mathrm{~J}$

Rachel B.
Rachel B.
Numerade Educator
02:23

Problem 41

If the heater were replaced by one having a greater resistance, the amount of heat produced each second would
(A) decrease
(B) increase
(C) remain the same

Rachel B.
Rachel B.
Numerade Educator
01:42

Problem 42

If another heater is connected in parallel with the first one and both operate at 120 volts, the current in the first heater will
(A) decrease
(B) increase
(C) remain the same

Rachel B.
Rachel B.
Numerade Educator
02:08

Problem 43

If the original heater were operated at fewer than 120 volts, the amount of heat produced would
(A) decrease
(B) increase
(C) remain the same

Rachel B.
Rachel B.
Numerade Educator
01:42

Problem 44

Base your answers to questions 44 through 49 on the diagram below, which represents an electric circuit. Charge is transferred from point $A$ to point $B$ at the rate of 5 coulombs per second for 120 seconds. Six joules of work are done in transferring each coulomb of charge.
What is the current in the wire?
(A) $1.2 \mathrm{~A}$
(B) $5 \mathrm{~A}$
(C) $6 \mathrm{~A}$
(D) $24 \mathrm{~A}$

Rachel B.
Rachel B.
Numerade Educator
02:26

Problem 45

What is the potential difference between points $A$ and $B$ ?
(A) $6 \mathrm{~V}$
(B) $30 \mathrm{~V}$
(C) $100 \mathrm{~V}$
(D) $600 \mathrm{~V}$

Rachel B.
Rachel B.
Numerade Educator
02:39

Problem 46

What is the rate at which work is done in this circuit?
(A) $6 \mathrm{~W}$
(B) $30 \mathrm{~W}$
(C) $144 \mathrm{~W}$
(D) $720 \mathrm{~W}$

Rachel B.
Rachel B.
Numerade Educator
02:59

Problem 47

What is the total work done in this circuit?
(A) $6 \mathrm{~J}$
(B) $30 \mathrm{~J}$
(C) $720 \mathrm{~J}$
(D) $3600 \mathrm{~J}$

Rachel B.
Rachel B.
Numerade Educator
03:30

Problem 48

What is the rate at which electrons are transferred in this circuit?
(A) $8 \times 10^{-19}$ electrons/s
(B) 5 electrons/s
(C) $1.1 \times 10^{18}$ electrons/s
(D) $3.1 \times 10^{19}$ electrons/s

Rachel B.
Rachel B.
Numerade Educator
03:26

Problem 49

What force moves 1 coulomb of charge from point $A$ to point $B$ ?
(A) $1 \mathrm{~N}$
(B) $5 \mathrm{~N}$
(C) $30 \mathrm{C}$
(D) $120 \mathrm{C}$

Rachel B.
Rachel B.
Numerade Educator
03:28

Problem 50

If $\mathrm{V}_{2}$ in the diagram reads 24 volts, $\mathrm{V}_{1}$ will read
(A) $8 \mathrm{~V}$
(B) $24 \mathrm{~V}$
(C) $48 \mathrm{~V}$
(D) $72 \mathrm{~V}$

Rachel B.
Rachel B.
Numerade Educator
05:31

Problem 51

Base your answers to questions 51 through 54 on the diagram below, which shows three resistors connected to a 15 -volt source.
The equivalent resistance of the circuit is
(A) $10 \Omega$
(B) $20 \Omega$
(C) $30 \Omega$
(D) $40 \Omega$

Rachel B.
Rachel B.
Numerade Educator
03:01

Problem 52

The total power developed in the circuit is
(A) $2.5 \mathrm{~W}$
(B) $5.0 \mathrm{~W}$
(C) $7.5 \mathrm{~W}$
(D) $10 \mathrm{~W}$

Rachel B.
Rachel B.
Numerade Educator
04:16

Problem 53

Compared to the heat developed in resistor $R_{1}$, the heat developed in resistor $R_{3}$ is
(A) one-third as great
(B) two times as great
(C) 3 times as great
(D) one-fourth as great

Rachel B.
Rachel B.
Numerade Educator
01:48

Problem 54

If resistor $R_{3}$ is removed and replaced by a resistor of lower value, the resistance of the circuit will
(A) decrease
(B) increase
(C) remain the same

Rachel B.
Rachel B.
Numerade Educator
01:13

Problem 55

The potential difference across $R_{1}$ is
(A) $\mathrm{OV}$
(B) $8.00 \mathrm{~V}$
(C) $12.0 \mathrm{~V}$
(D) $24.0 \mathrm{~V}$

Rachel B.
Rachel B.
Numerade Educator
01:29

Problem 56

What power is supplied by the source?
(A) $24.0 \mathrm{~W}$
(B) $90.0 \mathrm{~W}$
(C) $3.00 \mathrm{~W}$
(D) $192 \mathrm{~W}$

Rachel B.
Rachel B.
Numerade Educator
01:19

Problem 57

What is the current in resistor $R_{2}$ ?
(A) $8.00 \mathrm{~A}$
(B) $2.00 \mathrm{~A}$
(C) $16.0 \mathrm{~A}$
(D) $4.00 \mathrm{~A}$

Rachel B.
Rachel B.
Numerade Educator
04:53

Problem 58

The diagram below represents an electric circuit.
If the voltage between $A$ and $B$ is 10 volts, the voltage between $B$ and $C$ is
(A) $5 \mathrm{~V}$
(B) $10 \mathrm{~V}$
(C) $15 \mathrm{~V}$
(D) $20 \mathrm{~V}$

Rachel B.
Rachel B.
Numerade Educator
02:51

Problem 59

Compared to the potential drop across the 10-ohm resistor shown in the diagram, the potential difference across the 5 -ohm resistor is
(A) the same
(B) twice as great
(C) one-half as great
(D) 4 times as great

Rachel B.
Rachel B.
Numerade Educator
03:15

Problem 60

Ammeter $A$ in the diagram below will read 2 amperes when switch $B$ makes contact with which terminal?
(A) 1
(B) 2
(C) 3
(D) 4

Rachel B.
Rachel B.
Numerade Educator
02:49

Problem 61

As more resistors are added in series across a battery, the potential drop across each resistor
(A) decreases
(B) increases
(C) remains the same

Rachel B.
Rachel B.
Numerade Educator
01:43

Problem 62

A 5 -ohm resistor and a $10-$ ohm resistor are connected in series. If the current in the 5 -ohm resistor is doubled, the current in the 10-ohm resistor will
(A) be halved
(B) remain the same
(C) be doubled
(D) be quadrupled

Rachel B.
Rachel B.
Numerade Educator
03:43

Problem 63

Base your answers to questions 63 through 66 on the circuit diagram below. The reading of ammeter $A_{1}$ is $2.0$ amperes. Neglect the resistance of the connecting wires and the battery.
The potential difference supplied by battery $B$ is
(A) $1.0 \mathrm{~V}$
(B) $2.0 \mathrm{~V}$
(C) $6.0 \mathrm{~V}$
(D) $12 \mathrm{~V}$

Rachel B.
Rachel B.
Numerade Educator
03:59

Problem 64

How much heat energy will be produced by resistor $R_{1}$ in $3.0$ seconds?
(A) $72 \mathrm{~J}$
(B) $2.0 \mathrm{~J}$
(C) $12 \mathrm{~J}$
(D) $24 \mathrm{~J}$

Rachel B.
Rachel B.
Numerade Educator
02:01

Problem 65

How much charge will pass through resistor $R_{1}$ in $3.0$ seconds?
(A) $1.0 \mathrm{C}$
(B) $2.0 \mathrm{C}$
(C) $6.0 \mathrm{C}$
(D) $12 \mathrm{C}$

Rachel B.
Rachel B.
Numerade Educator
02:29

Problem 66

Compared to the potential difference across resistor $R_{3}$, the potential difference across resistor $R_{2}$ is
(A) one-half as much
(B) the same
(C) twice as much
(D) 3 times as much

Rachel B.
Rachel B.
Numerade Educator
02:55

Problem 67

If the current in the 10 -ohm resistor in the diagram is 1 ampere, then the current in the 40 -ohm resistor is
(A) $1 \mathrm{~A}$
(B) $0.25 \mathrm{~A}$
(C) $5 \mathrm{~A}$
(D) $4 \mathrm{~A}$

Rachel B.
Rachel B.
Numerade Educator
02:15

Problem 68

As additional resistors are connected in parallel to a source of constant voltage, the current in the circuit
(A) decreases
(B) increases
(C) remains the same

Rachel B.
Rachel B.
Numerade Educator
01:50

Problem 69

Base your answers to questions 69 through 72 on the diagram below, which shows three resistors connected in parallel to a 300 volt direct-current source.
A voltmeter connected between points $A$ and $B$ will have a reading of
(A) $20 \mathrm{~V}$
(B) $50 \mathrm{~V}$
(C) $100 \mathrm{~V}$
(D) $300 \mathrm{~V}$

Rachel B.
Rachel B.
Numerade Educator
01:46

Problem 70

What is the reading of ammeter $A_{3}$ ?
(A) $5.0 \mathrm{~A}$
(B) $15 \mathrm{~A}$
(C) $30 . \mathrm{A}$
(D) $55 \mathrm{~A}$

Rachel B.
Rachel B.
Numerade Educator
03:04

Problem 71

The greatest amount of current is through ammeter
(A) $\mathrm{A}_{1}$
(B) $\mathrm{A}_{2}$
(C) $\mathrm{A}_{3}$
(D) $\mathrm{A}_{4}$

Rachel B.
Rachel B.
Numerade Educator
02:17

Problem 72

Heat is produced by the 10-ohm resistor at a rate of
(A) $30 . \mathrm{W}$
(B) $3.0 \times 10^{2} \mathrm{~W}$
(C) $9.0 \times 10^{3} \mathrm{~W}$
(D) $3.0 \times 10^{3} \mathrm{~W}$

Rachel B.
Rachel B.
Numerade Educator
03:50

Problem 73

Which circuit below would have the lowest voltmeter reading?

Rachel B.
Rachel B.
Numerade Educator
01:59

Problem 74

Which circuit segment has an equivalent resistance of 6 ohms?

Supratim Pal
Supratim Pal
Numerade Educator
01:38

Problem 75

A circuit consists of a $10.0$-ohm resistor, a $15.0$-ohm resistor, and a 20.0-ohm resistor connected in parallel across a $9.00$-volt battery. What is the equivalent resistance of this circuit?
(A) $0.200 \Omega$
(B) $1.95 \Omega$
(C) $4.62 \Omega$
(D) $45.0 \Omega$

Rachel B.
Rachel B.
Numerade Educator
03:08

Problem 76

An electric circuit contains a variable resistor connected to a source of constant potential difference. Which graph best represents the relationship between current and resistance in this circuit?

Rachel B.
Rachel B.
Numerade Educator
01:40

Problem 77

In the circuit diagram below, two $4.0$-ohm resistors are connected to a 16-volt battery as shown.
The rate at which electrical energy is expended in this circuit is
(A) $8.0 \mathrm{~W}$
(B) $16 \mathrm{~W}$
(C) $32 \mathrm{~W}$
(D) $64 \mathrm{~W}$

Rachel B.
Rachel B.
Numerade Educator
01:22

Problem 78

The current through a 10.-ohm resistor is $1.2$ amperes. What is the potential difference across the resistor?
(A) $8.3 \mathrm{~V}$
(B) $12 \mathrm{~V}$
(C) $14 \mathrm{~V}$
(D) $120 \mathrm{~V}$

Rachel B.
Rachel B.
Numerade Educator
03:04

Problem 79

A copper wire of length $L$ and cross-sectional area $A$ has resistance $R$. A second copper wire at the same temperature has a length of $2 L$ and a cross-sectional area of $\frac{1}{2} A .$ What is the resistance of the second copper wire?
(A) $R$
(B) $2 R$
(C) $\frac{1}{2} R$
(D) $4 R$

Rachel B.
Rachel B.
Numerade Educator
03:32

Problem 80

A 6.0-ohm lamp requires $0.25$ ampere of current to operate. In which circuit below would the lamp operate correctly when switch $S$ is closed?

Rachel B.
Rachel B.
Numerade Educator
03:42

Problem 81

What is the total current in a circuit consisting of six operating 100-watt lamps connected in parallel to a 120 -volt source?
(A) $5 \mathrm{~A}$
(B) $20 \mathrm{~A}$
(C) $600 \mathrm{~A}$
(D) $12,000 \mathrm{~A}$

Rachel B.
Rachel B.
Numerade Educator
04:34

Problem 82

A 4.50-volt personal stereo uses 1950 joules of electrical energy in one hour. What is the electrical resistance of the personal stereo?
(A) $433 \Omega$
(B) $96.3 \Omega$
(C) $37.4 \Omega$
(D) $0.623 \Omega$

Rachel B.
Rachel B.
Numerade Educator
03:35

Problem 83

The diagram below represents a simple circuit consisting of a variable resistor, a battery, an ammeter, and a voltmeter.
What is the effect of increasing the resistance of the variable resistor from $1000 \Omega$ to $10,000 \Omega$ ? [Assume constant temperature.]
(A) The ammeter reading decreases.
(B) The ammeter reading increases.
(C) The voltmeter reading decreases.
(D) The voltmeter reading increases.

Rachel B.
Rachel B.
Numerade Educator
02:36

Problem 84

Base your answers to questions 84 through 86 on the diagram below, which represents an electric circuit consisting of four resistors and a 12 -volt battery.
What is the current measured by ammeter $A$ ?
(A) $0.50 \mathrm{~A}$
(B) $2.0 \mathrm{~A}$
(C) $72 \mathrm{~A}$
(D) $4.0 \mathrm{~A}$

Rachel B.
Rachel B.
Numerade Educator
02:08

Problem 85

What is the equivalent resistance of this circuit?
(A) $72 \Omega$
(B) $18 \Omega$
(C) $3.0 \Omega$
(D) $0.33 \Omega$

Rachel B.
Rachel B.
Numerade Educator
02:05

Problem 86

How much power is dissipated in the 36 -ohm resistor?
(A) $110 \mathrm{~W}$
(B) $48 \mathrm{~W}$
(C) $3.0 \mathrm{~W}$
(D) $4.0 \mathrm{~W}$

Rachel B.
Rachel B.
Numerade Educator
02:57

Problem 87

Which quantity and unit are correctly paired?
(A) resistivity and $\frac{\Omega}{\mathrm{m}}$
(B) potential difference and $\mathrm{eV}$
(C) current and C\cdots
(D) electric field strength and $\frac{\mathrm{N}}{\mathrm{C}}$

Rachel B.
Rachel B.
Numerade Educator
01:12

Problem 88

Which wavelength is in the infrared range of the electromagnetic spectrum?
(A) $100 \mathrm{~nm}$
(B) $100 \mathrm{~mm}$
(C) $100 \mathrm{~m}$
(D) $100 \mu \mathrm{m}$

Narayan Hari
Narayan Hari
Numerade Educator
01:49

Problem 89

What is the resistance at $20 .{ }^{\circ} \mathrm{C}$ of a $2.0$-meter length of tungsten wire with a cross-sectional area of $7.9 \times 10^{-7}$ meter $^{2}$ ?
(A) $5.7 \times 10^{-1} \Omega$
(B) $1.4 \times 10^{-1} \Omega$
(C) $7.1 \times 10^{-2} \Omega$
(D) $4.0 \times 10^{-2} \Omega$

Rachel B.
Rachel B.
Numerade Educator
01:43

Problem 90

A $6.0$-ohm resistor that obeys Ohm's law is connected to a source of variable potential difference. When the applied voltage is decreased from $12 \mathrm{~V}$ to $6.0 \mathrm{~V}$, the current passing through the resistor
(A) remains the same
(B) is doubled
(C) is halved
(D) is quadrupled

Rachel B.
Rachel B.
Numerade Educator
01:21

Problem 91

In which circuit represented below are meters properly connected to measure the current through resistor $R_{1}$ and the potential difference across resistor $R_{2} ?$

Supratim Pal
Supratim Pal
Numerade Educator
02:26

Problem 92

A 50 -watt lightbulb and a 10o-watt lightbulb are each operated at 110 volts. Compared to the resistance of the 50 -watt bulb, the resistance of the 100-watt bulb is
(A) half as great
(B) twice as great
(C) one-fourth as great
(D) four times as great

Rachel B.
Rachel B.
Numerade Educator
01:20

Problem 93

A device operating at a potential difference of $1.5$ volts draws a current of $0.20$ ampere. How much energy is used by the device in 6o. seconds?
(A) $4.5 \mathrm{~J}$
(B) $8.0 \mathrm{~J}$
(C) $12 \mathrm{~J}$
(D) $18 \mathrm{~J}$

Rachel B.
Rachel B.
Numerade Educator
02:18

Problem 94

As the number of resistors in a parallel circuit is increased, what happens to the equivalent resistance of the circuit and total current in the circuit?
(A) Both equivalent resistance and total current decrease.
(B) Both equivalent resistance and total current increase.
(C) Equivalent resistance decreases and total current increases.
(D) Equivalent resistance increases and total current decreases.

Rachel B.
Rachel B.
Numerade Educator
02:36

Problem 95

Pieces of aluminum, copper, gold, and silver wire each have the same length and the same cross-sectional area. Which wire has the lowest resistance at $20^{\circ} \mathrm{C}$ ?
(A) aluminum
(B) copper
(C) gold
(D) silver

Rachel B.
Rachel B.
Numerade Educator
03:09

Problem 96

The graph below represents the relationship between the potential difference ( $V$ ) across a resistor and the current (I) through the resistor.
Through which entire interval does the resistor obey Ohm's law?
(A) $A B$
(B) $B C$
(C) $C D$
(D) $A D$

Rachel B.
Rachel B.
Numerade Educator
01:05

Problem 97

How much electrical energy is required to move a $4.00-$ microcoulomb charge through a potential difference of $36.0$ volts?
(A) $9.00 \times 10^{6} \mathrm{~J}$
(B) $144 \mathrm{~J}$
(C) $1.44 \times 10^{-4} \mathrm{~J}$
(D) $1.11 \times 10^{-7} \mathrm{~J}$

Nishant Kumar
Nishant Kumar
Numerade Educator
01:20

Problem 98

What must be inserted between points $A$ and $B$ to establish a steady electric current in the incomplete circuit represented in the diagram below?
(A) switch
(B) voltmeter
(C) magnetic field source
(D) source of potential difference

Supratim Pal
Supratim Pal
Numerade Educator
01:49

Problem 99

In a series circuit containing two lamps, the battery supplies a potential difference of $1.5$ volts. If the current in the circuit is $0.10$ ampere, at what rate does the circuit use energy?
(A) $0.015 \mathrm{~W}$
(B) $0.15 \mathrm{~W}$
(C) $1.5 \mathrm{~W}$
(D) $15 \mathrm{~W}$

Rachel B.
Rachel B.
Numerade Educator
03:17

Problem 100

Which changes would cause the greatest increase in the rate of flow of charge through a conducting wire?
(A) increasing the applied potential difference and decreasing the length of wire
(B) increasing the applied potential difference and increasing the length of wire
(C) decreasing the applied potential difference and decreasing the length of wire
(D) decreasing the applied potential difference and increasing the length of wire

Rachel B.
Rachel B.
Numerade Educator