Question 1

Which of the following graphs best represents the current-voltage relationship of an incandescent light bulb?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) V 
A) I 
B) II 
C) III 
D) IV 
E) V

Question 2

For an ohmic substance, the electron drift velocity is proportional to:

Accepted Answer

A) the cross-sectional area of the sample 
B) the length of the sample 
C) the mass of an electron 
D) the electric field in the sample 
E) none of the above 
A) the cross-sectional area of the sample 
B) the length of the sample 
C) the mass of an electron 
D) the electric field in the sample 
E) none of the above

Question 3

The rate at which electrical energy is used may be measured in:

Accepted Answer

A) watt/second 
B) watt·second 
C) watt 
D) joule·second 
E) kilowatt·hour 
A) watt/second 
B) watt·second 
C) watt 
D) joule·second 
E) kilowatt·hour

Question 4

Two conductors are made of the same material and have the same length.Conductor A is a solid wire of diameter 1 m.Conductor B is a hollow tube of inside diameter 1 m and outside diameter 2 m.The ratio of their resistance, RA/RB, is:

Accepted Answer

A) 1 
B)    
C) 2 
D) 3 
E) 4 
A) 1 
B)    
C) 2 
D) 3 
E) 4

Question 5

A certain sample carries a current of 4 A when the potential difference is 2 V and a current of 10 A when the potential difference is 4 V.This sample:

Accepted Answer

A) obeys Ohm's law 
B) has a resistance of 0.5 $\Omega$ at 2 V 
C) has a resistance of 2 $\Omega$ at 2 V 
D) has a resistance of 25 $\Omega$ at 2 V 
E) does not have a resistance 
A) obeys Ohm's law 
B) has a resistance of 0.5 $\Omega$ at 2 V 
C) has a resistance of 2 $\Omega$ at 2 V 
D) has a resistance of 25 $\Omega$ at 2 V 
E) does not have a resistance

Question 6

Conductivity is:

Accepted Answer

A) the same as resistivity, it is just more convenient to use for good conductors 
B) expressed in $\Omega$-1 
C) equal to 1/resistance 
D) expressed in ($\Omega$.m)-1  
E) not a meaningful quantity for an insulator 
A) the same as resistivity, it is just more convenient to use for good conductors 
B) expressed in $\Omega$-1 
C) equal to 1/resistance 
D) expressed in ($\Omega$.m)-1  
E) not a meaningful quantity for an insulator

Question 7

Which of the following graphs best represents the current-voltage relationship for a device that obeys Ohm's law?

Accepted Answer

A) I 
B) II 
C) III 
D) IV 
E) V 
A) I 
B) II 
C) III 
D) IV 
E) V

Question 8

Which one of the following quantities is correctly matched to its unit?

Accepted Answer

A) power - kW·h 
B) energy - kW 
C) potential difference - J/C 
D) current - A/s 
E) resistance - V/C 
A) power - kW·h 
B) energy - kW 
C) potential difference - J/C 
D) current - A/s 
E) resistance - V/C

Question 9

Current is a measure of:

Accepted Answer

A) force that moves a charge past a point 
B) resistance to the movement of a charge past a point 
C) energy used to move a charge past a point 
D) amount of charge that moves past a point per unit time 
E) speed with which a charge moves past a point 
A) force that moves a charge past a point 
B) resistance to the movement of a charge past a point 
C) energy used to move a charge past a point 
D) amount of charge that moves past a point per unit time 
E) speed with which a charge moves past a point

Question 10

If the potential difference across a resistor is doubled:

Accepted Answer

A) only the current is doubled 
B) only the current is halved 
C) only the resistance is doubled 
D) only the resistance is halved 
E) both the current and resistance are doubled 
A) only the current is doubled 
B) only the current is halved 
C) only the resistance is doubled 
D) only the resistance is halved 
E) both the current and resistance are doubled

Question 11

Current in a conductor is normally due to:

Accepted Answer

A) the collective motion of all electrons in the conductor 
B) the thermal motion of the conduction electrons 
C) the drift motion of the conduction electrons due to electric fields 
D) the drift motion of both electrons and positrons 
E) the drift motion of both electrons and protons 
A) the collective motion of all electrons in the conductor 
B) the thermal motion of the conduction electrons 
C) the drift motion of the conduction electrons due to electric fields 
D) the drift motion of both electrons and positrons 
E) the drift motion of both electrons and protons

Question 12

A current of 0.5 ampere exists in a 60-ohm lamp.The applied potential difference is:

Accepted Answer

A) 15 V 
B) 30 V 
C) 60 V 
D) 120 V 
E) none of these 
A) 15 V 
B) 30 V 
C) 60 V 
D) 120 V 
E) none of these

Question 13

A certain x-ray tube requires a current of 7 mA at a voltage of 80 kV.The rate of energy dissipation is:

Accepted Answer

A) 5600 W 
B) 560 W 
C) 26 W 
D) 11.4 W 
E) 0.088 W 
A) 5600 W 
B) 560 W 
C) 26 W 
D) 11.4 W 
E) 0.088 W

Question 14

You wish to triple the rate of energy dissipation in a heating device.To do this you could triple:

Accepted Answer

A) the potential difference keeping the resistance the same 
B) the current keeping the resistance the same 
C) the resistance keeping the potential difference the same 
D) the resistance keeping the current the same 
E) both the potential difference and current 
A) the potential difference keeping the resistance the same 
B) the current keeping the resistance the same 
C) the resistance keeping the potential difference the same 
D) the resistance keeping the current the same 
E) both the potential difference and current

Question 15

A 10-ohm resistor has a constant current.If 1200 C of charge flow through it in 4 minutes what is the value of the current?

Accepted Answer

A) 3.0 A 
B) 5.0 A 
C) 20 A 
D) 120 A 
E) 300 A 
A) 3.0 A 
B) 5.0 A 
C) 20 A 
D) 120 A 
E) 300 A

Exam 26: Current and Resistance

Which of the following graphs best represents the current-voltage relationship of an incandescent light bulb?

For an ohmic substance, the electron drift velocity is proportional to:

The rate at which electrical energy is used may be measured in:

Two conductors are made of the same material and have the same length.Conductor A is a solid wire of diameter 1 m.Conductor B is a hollow tube of inside diameter 1 m and outside diameter 2 m.The ratio of their resistance, RA/RB, is:

A certain sample carries a current of 4 A when the potential difference is 2 V and a current of 10 A when the potential difference is 4 V.This sample:

Conductivity is:

Which of the following graphs best represents the current-voltage relationship for a device that obeys Ohm's law?

Which one of the following quantities is correctly matched to its unit?

Current is a measure of:

If the potential difference across a resistor is doubled:

Current in a conductor is normally due to:

A current of 0.5 ampere exists in a 60-ohm lamp.The applied potential difference is:

A certain x-ray tube requires a current of 7 mA at a voltage of 80 kV.The rate of energy dissipation is:

You wish to triple the rate of energy dissipation in a heating device.To do this you could triple:

A 10-ohm resistor has a constant current.If 1200 C of charge flow through it in 4 minutes what is the value of the current?

Measurement

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Vectors

Motion in Two and Three Dimensions

Force and Motion

Force and Motion

Kinetic Energy and Work

Potential Energy and Conservation of Energy

Center of Mass and Linear Momentum

Rotation

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Equilibrium and Elasticity

Gravitation

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Waves

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The Kinetic Theory of Gases

Entropy and the Second Law of Thermodynamics

Coulombs Law

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Maxwells Equations; Magnetism of Matter

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Energy From the Nucleus

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Filters

Two conductors are made of the same material and have the same length.Conductor A is a solid wire of diameter 1 m.Conductor B is a hollow tube of inside diameter 1 m and outside diameter 2 m.The ratio of their resistance, R_A/R_B, is: