Question 1

Which of the following relations among the quantities in the figure is generally correct?

Accepted Answer

A)  I1R1 = I2R2  
B)  I3R3 = I4R4  
C)  I1R1 = I4R4  
D)  I3R4 = I4R3  
E)  I1R1 + I2R2 = $\varepsilon$

Question 2

A 20-$\mu$F capacitor is charged to 200 V and is then connected across a 1000-$\Omega$ resistor. The amount of charge on the capacitor after 10 ms is approximately

Accepted Answer

A)  14 mC 
B)  2.4 mC 
C)  0.80 mC 
D)  1.6 mC 
E)  3.2 mC

Question 3

The power dissipated in the 16-$\Omega$ resistor in the figure is

Accepted Answer

A)  8.0 W 
B)  0.25 W 
C)  0.50 W 
D)  4.0 W 
E)  3.2 W

Question 4

Two copper wires have the same volume, but wire 2 is 20% longer than wire 1. The ratio of the resistances of the two wires R2/R1 is

Accepted Answer

A)  1.2 
B)  0.83 
C)  1.1 
D)  0.91 
E)  1.4

Question 5

The diagrams are schematic of a battery connected to a light bulb with a switch. When the switch is closed, which light bulb will come on?

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  all of them

Question 6

A wire of length L, cross sectional area A and resistance R is now drawn out by pulling such that its new resistance is 25R. What is its new cross sectional area? (Assume the density remains constant.)

Accepted Answer

A)  1.00 * 10-1 A 
B)  6.67 *10-1 A 
C)  4.00 * 10-1 A 
D)  2.50*10-1 A 
E)  2.00 *10-1 A

Question 7

Suppose instead of using a 12-gauge (diameter = 2.05 mm) solid copper cable you made a hollow copper cable of outer diameter 2.59 mm (10-gauge) and inner diameter
1)29 mm (16-gauge). Calculate the length of hollow cable that would give the same resistance as 1 m of 12-gauge solid cable. Use $\rho$(Cu) = 1.7 *10-8 $\Omega$/m.

Accepted Answer

A)  0.402 m 
B)  2.48 m 
C)  0.833 m 
D)  1.44 m 
E)  1.20 m

Question 8

When two resistors are connected in series, the equivalent resistance is Rs = 10  $\Omega$ . When they are connected in parallel, the equivalent resistance is Rp = 2.4  $\Omega$ . What are the values of the two resistances?

Accepted Answer

A)  4.0  $\Omega$  and 6.0  $\Omega$ 
B)  5.0  $\Omega$  for both 
C)  1.0  $\Omega$ and 1.4  $\Omega$ 
D)  1.2 $\Omega$  for both 
E)  2.5  $\Omega$ and 7.5  $\Omega$

Question 9

For copper, $\rho$ = 8.93 g/cm3 and M = 63.5 g/mol. Assuming one free electron per copper atom, what is the drift velocity of electrons in a copper wire of radius 0.625 mm carrying a current of 3 A?

Accepted Answer

A)  3.54 * 10-4 m/s 
B)  1.80 *10-4 m/s 
C)  4.26 * 10-4 m/s 
D)  7.52 *10-4 m/s 
E)  2.46 * 10-4 m/s

Question 10

An electric motor drives a pump that lifts water from a well that is 11.9 m deep and then delivers the water through a hose at a rate of 180 L/min and a speed of 21.0 m/s. If we assume 100% efficiency and ignore viscosity, the current drawn by the motor from a 220-V source is

Accepted Answer

A)  4.6 A 
B)  7.2 A 
C)  6.0 A 
D)  1.0 *103 A 
E)  2.3 A

Question 11

The total charge flowing per hour past a given point in a piece of electrical equipment rated at 550 kW and 110 V is

Accepted Answer

A)  1.8* 107 C 
B)  3.0 * 104 C 
C)  3.3 * 104 C 
D)  2.4 *103 C 
E)  impossible to determine without more information.

Question 12

A potential difference V = 25 V is applied across a wire of length L = 10.0 m and uniform diameter. The electric field throughout the wire is

Accepted Answer

A)  250 V/m 
B)  2.5 V/m 
C)  0.4 V/m 
D)  0.25 V/m 
E)  zero

Question 13

Four identical light bulbs are connected to a power supply as shown. Which light bulb consumes the most power?

Accepted Answer

A)  B1 
B)  B2 
C)  B3 
D)  B4 
E)  They all consume the same amount of power.

Question 14

A 20-$\mu$F capacitor is charged to 200 V and is then connected across a 1000-$\Omega$resistor. What is the initial charge on the capacitor?

Accepted Answer

A)  10 mC 
B)  5.6 mC 
C)  4.0 mC 
D)  8.0 mC 
E)  2.0 mC

Question 15

The curve that best represents the power loss in a resistor is

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 16

You want to determine the resistance R of a resistor by passing a current I through it, measuring this current with an ammeter connected in series with the resistor, measuring the voltage V across only the resistor with a voltmeter, and then dividing the voltage by the current to get the resistance. If the voltmeter has an internal resistance of 5.0 k$\Omega$, what is the percentage error (relative to the true value) in measuring a 1.0-k$\Omega$resistance?

Accepted Answer

A)  0.17% 
B)  1.7% 
C)  2.0% 
D)  17% 
E)  20%

Question 17

Two resistors are connected in parallel across a potential difference. The resistance of resistor A is twice that of resistor B. If the current carried by resistor A is I, what is the current carried by B?

Accepted Answer

A)  I 
B)  2I 
C)  I/2 
D)  4I 
E)  I/4

Question 18

In this circuit, two batteries, one with a potential difference of 10 V and the other with a potential difference of 20 V, are connected in series across a resistance of 90$\Omega$. The current in the circuit is

Accepted Answer

A)  3.0 A 
B)  0.33 A 
C)  9.0 A 
D)  30 A 
E)  4.5

Question 19

In a certain particle accelerator, a current of 300 $\mu$A is carried by a 4.00-MeV proton beam that has a radius of 1.30 mm. The mass of a proton is 1.67 *10-27 kg. If the beam hits a target, how many protons hit the target in 3 s?

Accepted Answer

A)  1.55 *1015  
B)  8.64 * 1015  
C)  3.42 * 1015  
D)  4.29 * 1015  
E)  None of these is correct.

Question 20

You connect two similar heating coils in series on a constant-voltage line. When you later connect them in parallel to the same line, the heat developed per minute, compared with the former rate, is approximately

Accepted Answer

A)  the same. 
B)  twice as great. 
C)  one-half as much. 
D)  four times as great. 
E)  one-fourth as much.

Exam 5: Electric Current and Direct-Current Circuits

A 20- $\mu$ F capacitor is charged to 200 V and is then connected across a 1000- $\Omega$ resistor. The amount of charge on the capacitor after 10 ms is approximately

$The power dissipated in the 16- \Omega resistor in the figure is A) 8.0 W B) 0.25 W C) 0.50 W D) 4.0 W E) 3.2 W$ The power dissipated in the 16- $\Omega$ resistor in the figure is

Two copper wires have the same volume, but wire 2 is 20% longer than wire 1. The ratio of the resistances of the two wires R₂/R₁ is

The diagrams are schematic of a battery connected to a light bulb with a switch. When the switch is closed, which light bulb will come on?

A wire of length L, cross sectional area A and resistance R is now drawn out by pulling such that its new resistance is 25R. What is its new cross sectional area? (Assume the density remains constant.)

When two resistors are connected in series, the equivalent resistance is R_s = 10 $\Omega$ . When they are connected in parallel, the equivalent resistance is R_p = 2.4 $\Omega$ . What are the values of the two resistances?

For copper, $\rho$ = 8.93 g/cm³ and M = 63.5 g/mol. Assuming one free electron per copper atom, what is the drift velocity of electrons in a copper wire of radius 0.625 mm carrying a current of 3 A?

An electric motor drives a pump that lifts water from a well that is 11.9 m deep and then delivers the water through a hose at a rate of 180 L/min and a speed of 21.0 m/s. If we assume 100% efficiency and ignore viscosity, the current drawn by the motor from a 220-V source is

The total charge flowing per hour past a given point in a piece of electrical equipment rated at 550 kW and 110 V is

A potential difference V = 25 V is applied across a wire of length L = 10.0 m and uniform diameter. The electric field throughout the wire is

Four identical light bulbs are connected to a power supply as shown. Which light bulb consumes the most power?

A 20- $\mu$ F capacitor is charged to 200 V and is then connected across a 1000- $\Omega$ resistor. What is the initial charge on the capacitor?

The curve that best represents the power loss in a resistor is

Two resistors are connected in parallel across a potential difference. The resistance of resistor A is twice that of resistor B. If the current carried by resistor A is I, what is the current carried by B?

In a certain particle accelerator, a current of 300 $\mu$ A is carried by a 4.00-MeV proton beam that has a radius of 1.30 mm. The mass of a proton is 1.67 *10^-27 kg. If the beam hits a target, how many protons hit the target in 3 s?

You connect two similar heating coils in series on a constant-voltage line. When you later connect them in parallel to the same line, the heat developed per minute, compared with the former rate, is approximately

Exam 5: Electric Current and Direct-Current Circuits

Which of the following relations among the quantities in the figure is generally correct?

A 20- μ\muμ F capacitor is charged to 200 V and is then connected across a 1000- Ω\OmegaΩ resistor. The amount of charge on the capacitor after 10 ms is approximately

The power dissipated in the 16- Ω\OmegaΩ resistor in the figure is

Two copper wires have the same volume, but wire 2 is 20% longer than wire 1. The ratio of the resistances of the two wires R2/R1 is

The diagrams are schematic of a battery connected to a light bulb with a switch. When the switch is closed, which light bulb will come on?

A wire of length L, cross sectional area A and resistance R is now drawn out by pulling such that its new resistance is 25R. What is its new cross sectional area? (Assume the density remains constant.)

When two resistors are connected in series, the equivalent resistance is Rs = 10 Ω\OmegaΩ . When they are connected in parallel, the equivalent resistance is Rp = 2.4 Ω\OmegaΩ . What are the values of the two resistances?

For copper, ρ\rhoρ = 8.93 g/cm3 and M = 63.5 g/mol. Assuming one free electron per copper atom, what is the drift velocity of electrons in a copper wire of radius 0.625 mm carrying a current of 3 A?

An electric motor drives a pump that lifts water from a well that is 11.9 m deep and then delivers the water through a hose at a rate of 180 L/min and a speed of 21.0 m/s. If we assume 100% efficiency and ignore viscosity, the current drawn by the motor from a 220-V source is

The total charge flowing per hour past a given point in a piece of electrical equipment rated at 550 kW and 110 V is

A potential difference V = 25 V is applied across a wire of length L = 10.0 m and uniform diameter. The electric field throughout the wire is

Four identical light bulbs are connected to a power supply as shown. Which light bulb consumes the most power?

A 20- μ\muμ F capacitor is charged to 200 V and is then connected across a 1000- Ω\OmegaΩ resistor. What is the initial charge on the capacitor?

The curve that best represents the power loss in a resistor is

Two resistors are connected in parallel across a potential difference. The resistance of resistor A is twice that of resistor B. If the current carried by resistor A is I, what is the current carried by B?

In this circuit, two batteries, one with a potential difference of 10 V and the other with a potential difference of 20 V, are connected in series across a resistance of 90 Ω\OmegaΩ . The current in the circuit is

In a certain particle accelerator, a current of 300 μ\muμ A is carried by a 4.00-MeV proton beam that has a radius of 1.30 mm. The mass of a proton is 1.67 *10-27 kg. If the beam hits a target, how many protons hit the target in 3 s?

You connect two similar heating coils in series on a constant-voltage line. When you later connect them in parallel to the same line, the heat developed per minute, compared with the former rate, is approximately

A 20- $\mu$ F capacitor is charged to 200 V and is then connected across a 1000- $\Omega$ resistor. The amount of charge on the capacitor after 10 ms is approximately

$The power dissipated in the 16- \Omega resistor in the figure is A) 8.0 W B) 0.25 W C) 0.50 W D) 4.0 W E) 3.2 W$ The power dissipated in the 16- $\Omega$ resistor in the figure is

Two copper wires have the same volume, but wire 2 is 20% longer than wire 1. The ratio of the resistances of the two wires R₂/R₁ is

When two resistors are connected in series, the equivalent resistance is R_s = 10 $\Omega$ . When they are connected in parallel, the equivalent resistance is R_p = 2.4 $\Omega$ . What are the values of the two resistances?

For copper, $\rho$ = 8.93 g/cm³ and M = 63.5 g/mol. Assuming one free electron per copper atom, what is the drift velocity of electrons in a copper wire of radius 0.625 mm carrying a current of 3 A?

A 20- $\mu$ F capacitor is charged to 200 V and is then connected across a 1000- $\Omega$ resistor. What is the initial charge on the capacitor?

In a certain particle accelerator, a current of 300 $\mu$ A is carried by a 4.00-MeV proton beam that has a radius of 1.30 mm. The mass of a proton is 1.67 *10^-27 kg. If the beam hits a target, how many protons hit the target in 3 s?