Question 1

For the graph shown in the figure, what physical quantity does the slope of the graph represent for ohmic material?

Accepted Answer

A)  resistance 
B)  power 
C)  resistivity 
D)  $1 /$ (resistivity) 
E)  $1 / ($ resistance) 
A)  resistance 
B)  power 
C)  resistivity 
D)  $1 /$ (resistivity) 
E)  $1 / ($ resistance)

Question 2

How much does it cost to operate a 25-W soldering iron for 8.0 hours if energy costs 8.0¢/kWh?

Accepted Answer

A)  $16 \phi$ 
B)  $25 \phi$ 
C)  $\$ 1.50$ 
D)  $1.6 \phi$ 
A)  $16 \phi$ 
B)  $25 \phi$ 
C)  $\$ 1.50$ 
D)  $1.6 \phi$

Question 3

If a quantity you calculated has units of $\frac { \mathrm { kg } \cdot \mathrm { m } ^ { 3 } } { \mathrm {~s} \cdot \mathrm { C } ^ { 2 } }$ what is that quantity?

Accepted Answer

A)  resistance 
B)  current 
C)  capacitance 
D)  potential 
E)  resistivity 
A)  resistance 
B)  current 
C)  capacitance 
D)  potential 
E)  resistivity

Question 4

The figure shows a graph of the power dissipated in a resistor as a function of the resistance. What quantity does the slope of this graph represent?

Accepted Answer

A)  the square of the current in the resistor 
B)  the potential difference across the resistor 
C)  the reciprocal of the current in the resistor 
D)  the current in the resistor 
E)  the resistivity of the resistor 
A)  the square of the current in the resistor 
B)  the potential difference across the resistor 
C)  the reciprocal of the current in the resistor 
D)  the current in the resistor 
E)  the resistivity of the resistor

Question 5

A resistor operated at $120 \mathrm {~V} \mathrm { dc }$ is rated at $1.40 \mathrm {~kW}$.
(a) What is the normal operating current through the resistor?
(b) What is the resistance of the resistor?

Accepted Answer

The answer of A resistor operated at \(120 \mathrm {~V}...

Question 6

How much energy does a 100-W light bulb use in 8.0 hours?

Accepted Answer

A)  $0.0080 \mathrm { kWh }$ 
B)  $13 \mathrm { kWh }$ 
C)  $0.80 \mathrm { kWh }$ 
D)  $800 \mathrm { kWh }$ 
A)  $0.0080 \mathrm { kWh }$ 
B)  $13 \mathrm { kWh }$ 
C)  $0.80 \mathrm { kWh }$ 
D)  $800 \mathrm { kWh }$

Question 7

The resistivity of a $1.0 \mathrm {~m}$ long copper wire is $1.72 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }$ and its cross sectional area is $2.0 \times$ $10 ^ { - 6 } \mathrm {~m} ^ { 2 }$. If the wire carries a current of $0.20 \mathrm {~A}$, what is the voltage across the wire?

Accepted Answer

A)  $1.7 \mathrm { mV }$ 
B)  $17 \mathrm { mV }$ 
C)  $0.90 \mathrm { mV }$ 
D)  $90 \mathrm { mV }$ 
E)  $10 \mathrm { mV }$ 
A)  $1.7 \mathrm { mV }$ 
B)  $17 \mathrm { mV }$ 
C)  $0.90 \mathrm { mV }$ 
D)  $90 \mathrm { mV }$ 
E)  $10 \mathrm { mV }$

Question 8

The resistivity of the material of a wire is $1.76 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }$. If the diameter of the wire is $2.00 \mathrm {~mm}$ and its length is $2.00 \mathrm {~m}$, what is its resistance?

Accepted Answer

A)  $11.2 \Omega$ 
B)  $1.12 \Omega$ 
C)  $0.0112 \Omega$ 
D)  $112 \Omega$ 
E)  $0.112 \Omega$ 
A)  $11.2 \Omega$ 
B)  $1.12 \Omega$ 
C)  $0.0112 \Omega$ 
D)  $112 \Omega$ 
E)  $0.112 \Omega$

Question 9

Over ordinary temperature ranges, the resistance of most metals such as copper

Accepted Answer

A)  is a maximum at $20 ^ { \circ } \mathrm { C }$. 
B)  increases as the metal gets hotter. 
C)  is independent of the temperature of the metal. 
D)  decreases as the metal gets hotter. 
A)  is a maximum at $20 ^ { \circ } \mathrm { C }$. 
B)  increases as the metal gets hotter. 
C)  is independent of the temperature of the metal. 
D)  decreases as the metal gets hotter.

Question 10

A wire of resistivity @ must be replaced in a circuit by a wire of the same material but four times as long. If, however, the total resistance is to remain as before, the diameter of the new wire must

Accepted Answer

A)  be the same as the original diameter. 
B)  be one-fourth the original diameter. 
C)  be four times the original diameter. 
D)  be two times the original diameter. 
E)  be one-half the original diameter. 
A)  be the same as the original diameter. 
B)  be one-fourth the original diameter. 
C)  be four times the original diameter. 
D)  be two times the original diameter. 
E)  be one-half the original diameter.

Question 11

A certain metal has a resistivity of $1.68 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }$. You have a long spool of wire made from this metal. If this wire has a diameter of $0.15 \mathrm {~mm}$, how long should you cut a segment so its resistance will be $15 \Omega$ ?

Accepted Answer

A)  $16 \mathrm {~m}$ 
B)  $1.6 \mathrm {~m}$ 
C)  $16 \mathrm {~mm}$ 
D)  $16 \mathrm {~cm}$ 
A)  $16 \mathrm {~m}$ 
B)  $1.6 \mathrm {~m}$ 
C)  $16 \mathrm {~mm}$ 
D)  $16 \mathrm {~cm}$

Question 12

What potential difference is required across an 8.0-Ω resistor to cause 2.0 A to flow
through it?

Accepted Answer

The answer of What potential difference is required across an...

Question 13

When a thin copper wire that is $178 \mathrm {~m}$ long is connected between a $1.2 - \mathrm { V }$ potential difference, a current of $2.0$ amps flows through the wire. What is the diameter of this wire? The resistivity of copper is $1.72 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }$.

Accepted Answer

The answer of When a thin copper wire that is...

Question 14

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?

Accepted Answer

A)  resistance 
B)  resistivity 
C)  $1 /$ (current) 
D)  current 
E)  $1 /$ (resistance) 
A)  resistance 
B)  resistivity 
C)  $1 /$ (current) 
D)  current 
E)  $1 /$ (resistance)

Question 15

The length of a certain wire is doubled while its radius is kept constant. What is the new resistance of this wire?

Accepted Answer

A)  It is 3 times as large. 
B)  It is 2 times as large. 
C)  It stays the same. 
D)  It is $1 / 2$ as large. 
E)  It is 4 times as large. 
A)  It is 3 times as large. 
B)  It is 2 times as large. 
C)  It stays the same. 
D)  It is $1 / 2$ as large. 
E)  It is 4 times as large.

Question 16

A electric heater that draws $13.5 \mathrm {~A}$ of dc current has been left on for $10 \mathrm {~min}$. How many electrons that have passed through the heater during that time? (e $\left. = 1.60 \times 10 ^ { - 19 } \mathrm { C } \right)$

Accepted Answer

A)  $8.1 \times 10 ^ { 3 }$ 
B)  $5.1 \times 10 ^ { 22 }$ 
C)  $1.0 \times 10 ^ { 23 }$ 
D)  $1.5 \times 10 ^ { 22 }$ 
E)  $1.8 \times 10 ^ { 3 }$ 
A)  $8.1 \times 10 ^ { 3 }$ 
B)  $5.1 \times 10 ^ { 22 }$ 
C)  $1.0 \times 10 ^ { 23 }$ 
D)  $1.5 \times 10 ^ { 22 }$ 
E)  $1.8 \times 10 ^ { 3 }$

Question 17

A tungsten wire is $1.50 \mathrm {~m}$ long and has a diameter of $1.00 \mathrm {~mm}$. At $20 ^ { \circ } \mathrm { C }$ a current of $50 \mathrm {~mA}$ flows through this wire. The temperature coefficient of resistivity for this tungsten is $4.5 \times$ $10 ^ { - 3 } / \mathrm { C } ^ { \circ }$, and its resistivity at $20 ^ { \circ } \mathrm { C }$ is $5.6 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }$.
(a) What is the potential difference across the ends of this wire at $20 ^ { \circ } \mathrm { C }$ ?
(b) If the wire temperature increases by $100 \mathrm { C } ^ { \circ }$, what potential difference across its ends is now required to produce a current of $50 \mathrm {~mA}$ ?

Accepted Answer

(a) 5.3 mV

Question 18

A 9.0-V battery costs $1.49 and will run a portable CD player for 6.0 hours before running down and needing to be replaced. If this battery supplies a current of 25 mA to the player, what is the
Cost of the energy provided by the battery in dollars per kWh?

Accepted Answer

A)  $\$ 11,000 / \mathrm { kWh }$ 
B)  $\$ 110 / \mathrm { kWh }$ 
C)  $\$ 11 / \mathrm { kWh }$ 
D)  $\$ 1100 / \mathrm { kWh }$ 
A)  $\$ 11,000 / \mathrm { kWh }$ 
B)  $\$ 110 / \mathrm { kWh }$ 
C)  $\$ 11 / \mathrm { kWh }$ 
D)  $\$ 1100 / \mathrm { kWh }$

Question 19

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?

Accepted Answer

A)  capacitance 
B)  current 
C)  energy 
D)  resistance 
E)  resistivity 
A)  capacitance 
B)  current 
C)  energy 
D)  resistance 
E)  resistivity

Question 20

What is the resistance of $1.0 \mathrm {~m}$ of a solid cylindrical metal cable having a diameter of $0.40$ inches and a resistivity of $1.68 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }$ ?

Accepted Answer

A)  $0.00021 \Omega$ 
B)  $0.0012 \Omega$ 
C)  $0.0021 \Omega$ 
D)  $0.00012 \Omega$ 
A)  $0.00021 \Omega$ 
B)  $0.0012 \Omega$ 
C)  $0.0021 \Omega$ 
D)  $0.00012 \Omega$

Exam 18: Electric Currents

For the graph shown in the figure, what physical quantity does the slope of the graph represent for ohmic material?

How much does it cost to operate a 25-W soldering iron for 8.0 hours if energy costs 8.0¢/kWh?

If a quantity you calculated has units of kg⋅m3 s⋅C2\frac { \mathrm { kg } \cdot \mathrm { m } ^ { 3 } } { \mathrm {~s} \cdot \mathrm { C } ^ { 2 } } s⋅C2kg⋅m3​ what is that quantity?

The figure shows a graph of the power dissipated in a resistor as a function of the resistance. What quantity does the slope of this graph represent?

A resistor operated at 120 Vdc120 \mathrm {~V} \mathrm { dc }120 Vdc is rated at 1.40 kW1.40 \mathrm {~kW}1.40 kW . (a) What is the normal operating current through the resistor? (b) What is the resistance of the resistor?

How much energy does a 100-W light bulb use in 8.0 hours?

The resistivity of the material of a wire is 1.76×10−8Ω⋅m1.76 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }1.76×10−8Ω⋅m . If the diameter of the wire is 2.00 mm2.00 \mathrm {~mm}2.00 mm and its length is 2.00 m2.00 \mathrm {~m}2.00 m , what is its resistance?

Over ordinary temperature ranges, the resistance of most metals such as copper

A wire of resistivity @ must be replaced in a circuit by a wire of the same material but four times as long. If, however, the total resistance is to remain as before, the diameter of the new wire must

What potential difference is required across an 8.0-Ω resistor to cause 2.0 A to flow through it?

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?

The length of a certain wire is doubled while its radius is kept constant. What is the new resistance of this wire?

A electric heater that draws 13.5 A13.5 \mathrm {~A}13.5 A of dc current has been left on for 10 min10 \mathrm {~min}10 min . How many electrons that have passed through the heater during that time? (e =1.60×10−19C)\left. = 1.60 \times 10 ^ { - 19 } \mathrm { C } \right)=1.60×10−19C)

A 9.0-V battery costs $1.49 and will run a portable CD player for 6.0 hours before running down and needing to be replaced. If this battery supplies a current of 25 mA to the player, what is the Cost of the energy provided by the battery in dollars per kWh?

For the graph shown in the figure, what physical quantity does the slope of the graph represent for a dc circuit?

What is the resistance of 1.0 m1.0 \mathrm {~m}1.0 m of a solid cylindrical metal cable having a diameter of 0.400.400.40 inches and a resistivity of 1.68×10−8Ω⋅m1.68 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }1.68×10−8Ω⋅m ?

Introduction, Measurement, Estimating

Describing Motion: Kinematics in One Dimension

Kinematics in Two Dimensions; Vectors

Dynamics: Newtons Laws of Motion

Circular Motion; Gravitation

Work and Energy

Linear Momentum

Rotational Motion

Static Equilibrium; Elasticity and Fracture

Fluids

Oscillations and Waves

Sound

Temperature and Kinetic Theory

Heat

The Laws of Thermodynamics

Electric Charge and Electric Field

Electric Potential

Dc Circuits

Magnetism

Electromagnetic Induction and Faradays Law

Electromagnetic Waves

Light: Geometric Optics

The Wave Nature of Light

Optical Instruments

The Special Theory of Relativity

Early Quantum Theory and Models of the Atom

Quantum Mechanics of Atoms

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Nuclear Energy; Effects and Uses of Radiation

Elementary Particles

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Filters

If a quantity you calculated has units of $\frac { \mathrm { kg } \cdot \mathrm { m } ^ { 3 } } { \mathrm {~s} \cdot \mathrm { C } ^ { 2 } }$ what is that quantity?

A resistor operated at $120 \mathrm {~V} \mathrm { dc }$ is rated at $1.40 \mathrm {~kW}$ . (a) What is the normal operating current through the resistor? (b) What is the resistance of the resistor?

The resistivity of the material of a wire is $1.76 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }$ . If the diameter of the wire is $2.00 \mathrm {~mm}$ and its length is $2.00 \mathrm {~m}$ , what is its resistance?

A electric heater that draws $13.5 \mathrm {~A}$ of dc current has been left on for $10 \mathrm {~min}$ . How many electrons that have passed through the heater during that time? (e $\left. = 1.60 \times 10 ^ { - 19 } \mathrm { C } \right)$

What is the resistance of $1.0 \mathrm {~m}$ of a solid cylindrical metal cable having a diameter of $0.40$ inches and a resistivity of $1.68 \times 10 ^ { - 8 } \Omega \cdot \mathrm { m }$ ?