Question 1

The quantity volt is equivalent to which of the following?

Accepted Answer

A)  J*m
B)  J*C
C)  C/W
D)  J/CE) A) and C)
F) B) and C)

Question 2

A solar panel measures 80 cm * 50 cm.In direct sunlight, the panel delivers 3.2 A at 15 V.If the intensity of sunlight is 1 000 W/m2, what is the efficiency of the solar panel in converting solar energy into electrical energy?

Accepted Answer

A)  24%
B)  18%
C)  12%
D)  6.0%E) A) and B)
F) B) and C)

Question 3

A water pump draws about 3.8 A when connected to 240 V.What is the cost (with electrical energy at 9 cents per kWh)  of running the pump for 10 h?

Accepted Answer

A)  8.0 cents
B)  15 cents
C)  82 cents
D)  95 centsE) A) and C)
F) None of the above

Question 4

A resistor is made of a material that has a resistivity that is proportional to the current going through it. If the voltage across the resistor is doubled, what happens to the current through it?

Accepted Answer

A)  It doubles.
B)  It quadruples.
C)  It increases by a factor of 23/2.
D)  It increases by a factor of 21/2.E) A) and D)
F) A) and B)

Question 5

When you flip a switch to turn on a light, the delay before the light turns on is determined by:

Accepted Answer

A)  the number of electron collisions per second in the wire.
B)  the drift speed of the electrons in the wire.
C)  the speed of the electric field moving in the wire.
D)  none of these, since the light comes on instantly.E) A) and C)
F) A) and B)

Question 6

Number 10 copper wire (radius = 1.3 mm)  is commonly used for electrical installations in homes.What is the voltage drop in 40 m of #10 copper wire if it carries a current of 10 A? (The resistivity of copper is 1.7 * 10-8 W*m.)

Accepted Answer

A)  1.3 V
B)  0.77 V
C)  0.50 V
D)  0.13 VE) C) and D)
F) A) and C)

Question 7

Wire A and Wire B are each carrying the same current.If the diameter of Wire A is twice that of Wire B, how does the drift velocity vdA in Wire A compare to that in in Wire B?

Accepted Answer

A)  vdA = vdB
B)  vdA = 2 vdB
C)  vdA = vdB /2
D)  vdA = vdB /4E) None of the above
F) A) and D)

Question 8

Some superconductors are capable of carrying a very large quantity of current.If the measured current is 1.00 * 105 A, how many electrons are moving through the superconductor per second? (e = 1.60 * 10-19 C)

Accepted Answer

A)  6.25 * 1023
B)  3.12 * 1022
C)  6.25 * 1021
D)  3.12 * 1020E) C) and D)
F) B) and C)

Question 9

Two wires with the same resistance have the same diameter but different lengths.If wire 1 has length L1 and wire 2 has length L2, how do L1 and L2 compare if wire 1 is made from copper and wire 2 is made from aluminum? The resistivity of copper is 1.7 * 10-5 W·m and the resistivity of aluminum is 2.82 * 10-5 W·m.

Accepted Answer

A)  L1 = 1.7 L2
B)  L1 = 0.60 L2
C)  L1 = 2.8 L2
D)  L1 = 0.36 L2E) A) and B)
F) B) and C)

Question 10

A wire 1 mm in diameter is connected to one end of a wire of the same material 2 mm in diameter of twice the length.A voltage source is connected to the wires and a current is passed through the wires.If it takes time T for the average conduction electron to traverse the 1-mm wire, how long does it take for such an electron to traverse the 2-mm wire?

Accepted Answer

A)  T/4
B)  T
C)  4T
D)  8TE) A) and B)
F) None of the above D

Question 11

Which is a unit of power?

Accepted Answer

A)  kWh
B)  W/s
C)  A*W
D)  J/sE) C) and D)
F) A) and B)

Question 12

If a 500-W heater carries a current of 4.00 A, what is the voltage across the ends of the heating element?

Accepted Answer

A)  2 000 V
B)  125 V
C)  250 V
D)  0.008 VE) A) and B)
F) All of the above

Question 13

Superconductivity was discovered by:

Accepted Answer

A)  Volta.
B)  Ohm.
C)  Onnes.
D)  Bednorz and Müller.E) B) and C)
F) None of the above

Question 14

The current in an electron beam in a cathode-ray tube is measured to be 70 µA.How many electrons hit the screen in 5.0 s? (e = 1.6 * 10-19 C)

Accepted Answer

A)  2.2 * 1011 electrons
B)  8.8 * 1013 electrons
C)  2.2 * 1015 electrons
D)  8.8 * 1018 electronsE) A) and B)
F) B) and C)

Question 15

A high-voltage transmission line carries 1 000 A at 700 000 V.What is the power carried by the line?

Accepted Answer

A)  700 MW
B)  370 MW
C)  100 MW
D)  70 MWE) A) and D)
F) B) and D)

Question 16

Materials having resistance changes as voltage or current varies are called:

Accepted Answer

A)  ohmic.
B)  inohmic.
C)  nonohmic.
D)  deohmic.E) A) and C)
F) C) and D)

Question 17

The size of the electric current in a electrical conductor is a function of which of the following?

Accepted Answer

A)  velocity of charge carriers
B)  conductor cross sectional area
C)  density of charge carriers
D)  All of the above choices are valid.E) C) and D)
F) A) and C)

Question 18

A 20-W platinum wire at 20 °\degree° C with a temperature coefficient of resistivity of 3.9 * 10-3 ( °\degree° C) -1 will have what resistance at 100 °\degree° C?

Accepted Answer

A)  14 W
B)  20 W
C)  26 W
D)  28 W E) A) and C)
F) B) and D) C

Question 19

The resistivity of a material is doubled when heated a certain amount.What happens to the resistance of a resistor made of this material when heated the same amount?

Accepted Answer

A)  It doubles.
B)  It quadruples.
C)  It halves.
D)  It stays the same.E) B) and D)
F) A) and B) A

Question 20

A steam turbine at an electric power plant delivers 4 500 kW of power to an electrical generator which converts 95% of this mechanical energy into electrical energy.What is the current delivered by the generator if it delivers at 3 600 V?

Accepted Answer

A)  0.66 * 103 A
B)  1.0 * 103 A
C)  1.2 * 103 A
D)  5.9 * 103 AE) A) and B)
F) A) and C)

Exam 17: Current and Resistance

The quantity volt is equivalent to which of the following?

Correct Answer
verified

A solar panel measures 80 cm * 50 cm.In direct sunlight, the panel delivers 3.2 A at 15 V.If the intensity of sunlight is 1 000 W/m², what is the efficiency of the solar panel in converting solar energy into electrical energy?

Correct Answer
verified

A water pump draws about 3.8 A when connected to 240 V.What is the cost (with electrical energy at 9 cents per kWh) of running the pump for 10 h?

Correct Answer
verified

A resistor is made of a material that has a resistivity that is proportional to the current going through it. If the voltage across the resistor is doubled, what happens to the current through it?

Correct Answer
verified

When you flip a switch to turn on a light, the delay before the light turns on is determined by:

Correct Answer
verified

Number 10 copper wire (radius = 1.3 mm) is commonly used for electrical installations in homes.What is the voltage drop in 40 m of #10 copper wire if it carries a current of 10 A? (The resistivity of copper is 1.7 * 10^-8 W*m.)

Correct Answer
verified

Wire A and Wire B are each carrying the same current.If the diameter of Wire A is twice that of Wire B, how does the drift velocity v_dA in Wire A compare to that in in Wire B?

Correct Answer
verified

Some superconductors are capable of carrying a very large quantity of current.If the measured current is 1.00 * 10⁵A, how many electrons are moving through the superconductor per second? (e = 1.60 * 10^-19 C)

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
D

Which is a unit of power?

Correct Answer
verified

If a 500-W heater carries a current of 4.00 A, what is the voltage across the ends of the heating element?

Correct Answer
verified

Superconductivity was discovered by:

Correct Answer
verified

The current in an electron beam in a cathode-ray tube is measured to be 70 µA.How many electrons hit the screen in 5.0 s? (e = 1.6 * 10^-19 C)

Correct Answer
verified

A high-voltage transmission line carries 1 000 A at 700 000 V.What is the power carried by the line?

Correct Answer
verified

Materials having resistance changes as voltage or current varies are called:

Correct Answer
verified

The size of the electric current in a electrical conductor is a function of which of the following?

Correct Answer
verified

A 20-W platinum wire at 20 $\degree$ C with a temperature coefficient of resistivity of 3.9 * 10^-3 ( $\degree$ C) ^-1 will have what resistance at 100 $\degree$ C?

Correct Answer
verified
C

The resistivity of a material is doubled when heated a certain amount.What happens to the resistance of a resistor made of this material when heated the same amount?

Correct Answer
verified
A

A steam turbine at an electric power plant delivers 4 500 kW of power to an electrical generator which converts 95% of this mechanical energy into electrical energy.What is the current delivered by the generator if it delivers at 3 600 V?

Correct Answer
verified

Exam 17: Current and Resistance

The quantity volt is equivalent to which of the following?

Correct AnswerverifiedShow Answer

A solar panel measures 80 cm * 50 cm.In direct sunlight, the panel delivers 3.2 A at 15 V.If the intensity of sunlight is 1 000 W/m2, what is the efficiency of the solar panel in converting solar energy into electrical energy?

Correct AnswerverifiedShow Answer

A water pump draws about 3.8 A when connected to 240 V.What is the cost (with electrical energy at 9 cents per kWh) of running the pump for 10 h?

Correct AnswerverifiedShow Answer

A resistor is made of a material that has a resistivity that is proportional to the current going through it. If the voltage across the resistor is doubled, what happens to the current through it?

Correct AnswerverifiedShow Answer

When you flip a switch to turn on a light, the delay before the light turns on is determined by:

Correct AnswerverifiedShow Answer

Number 10 copper wire (radius = 1.3 mm) is commonly used for electrical installations in homes.What is the voltage drop in 40 m of #10 copper wire if it carries a current of 10 A? (The resistivity of copper is 1.7 * 10-8 W*m.)

Correct AnswerverifiedShow Answer

Wire A and Wire B are each carrying the same current.If the diameter of Wire A is twice that of Wire B, how does the drift velocity vdA in Wire A compare to that in in Wire B?

Correct AnswerverifiedShow Answer

Some superconductors are capable of carrying a very large quantity of current.If the measured current is 1.00 * 105 A, how many electrons are moving through the superconductor per second? (e = 1.60 * 10-19 C)

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerverifiedD

Which is a unit of power?

Correct AnswerverifiedShow Answer

If a 500-W heater carries a current of 4.00 A, what is the voltage across the ends of the heating element?

Correct AnswerverifiedShow Answer

Superconductivity was discovered by:

Correct AnswerverifiedShow Answer

The current in an electron beam in a cathode-ray tube is measured to be 70 µA.How many electrons hit the screen in 5.0 s? (e = 1.6 * 10-19 C)

Correct AnswerverifiedShow Answer

A high-voltage transmission line carries 1 000 A at 700 000 V.What is the power carried by the line?

Correct AnswerverifiedShow Answer

Materials having resistance changes as voltage or current varies are called:

Correct AnswerverifiedShow Answer

The size of the electric current in a electrical conductor is a function of which of the following?

Correct AnswerverifiedShow Answer

A 20-W platinum wire at 20 °\degree° C with a temperature coefficient of resistivity of 3.9 * 10-3 ( °\degree° C) -1 will have what resistance at 100 °\degree° C?

Correct AnswerverifiedC

The resistivity of a material is doubled when heated a certain amount.What happens to the resistance of a resistor made of this material when heated the same amount?

Correct AnswerverifiedA

A steam turbine at an electric power plant delivers 4 500 kW of power to an electrical generator which converts 95% of this mechanical energy into electrical energy.What is the current delivered by the generator if it delivers at 3 600 V?

Correct AnswerverifiedShow Answer

Correct Answer
verified

A solar panel measures 80 cm * 50 cm.In direct sunlight, the panel delivers 3.2 A at 15 V.If the intensity of sunlight is 1 000 W/m², what is the efficiency of the solar panel in converting solar energy into electrical energy?

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Number 10 copper wire (radius = 1.3 mm) is commonly used for electrical installations in homes.What is the voltage drop in 40 m of #10 copper wire if it carries a current of 10 A? (The resistivity of copper is 1.7 * 10^-8 W*m.)

Correct Answer
verified

Wire A and Wire B are each carrying the same current.If the diameter of Wire A is twice that of Wire B, how does the drift velocity v_dA in Wire A compare to that in in Wire B?

Correct Answer
verified

Some superconductors are capable of carrying a very large quantity of current.If the measured current is 1.00 * 10⁵A, how many electrons are moving through the superconductor per second? (e = 1.60 * 10^-19 C)

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
D

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

The current in an electron beam in a cathode-ray tube is measured to be 70 µA.How many electrons hit the screen in 5.0 s? (e = 1.6 * 10^-19 C)

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

A 20-W platinum wire at 20 $\degree$ C with a temperature coefficient of resistivity of 3.9 * 10^-3 ( $\degree$ C) ^-1 will have what resistance at 100 $\degree$ C?

Correct Answer
verified
C

Correct Answer
verified
A

Correct Answer
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