Question 1

The power dissipated in the 21-$\Omega$ resistor in this circuit is

Accepted Answer

A)  14 W 
B)  68 W 
C)  43 W 
D)  13 W 
E)  None of these is correct. 
A)  14 W 
B)  68 W 
C)  43 W 
D)  13 W 
E)  None of these is correct.

Question 2

Two pieces of copper wire have the same length, but wire A has a square cross section of width s whereas wire B has a circular cross section of diameter s. Which of the following statements is true?

Accepted Answer

A)  The resistance of both wires is the same. 
B)  The resistivity of both wires is the same. 
C)  Both the resistance and the resistivity of A and B are the same. 
D)  The resistance of A is greater than that of B. 
E)  The resistivity of A is greater than that of B. 
A)  The resistance of both wires is the same. 
B)  The resistivity of both wires is the same. 
C)  Both the resistance and the resistivity of A and B are the same. 
D)  The resistance of A is greater than that of B. 
E)  The resistivity of A is greater than that of B.

Question 3

In the diagram above, the voltage difference between a and b is 6 V. If R1 = 25 $\Omega$, R3 = 45 $\Omega$, and I = 0.095 A, then find the current flowing through R2.

Accepted Answer

A)  0.026 A 
B)  0.015 A 
C)  0.037 A 
D)  0.080 A 
E)  0.070 A 
A)  0.026 A 
B)  0.015 A 
C)  0.037 A 
D)  0.080 A 
E)  0.070 A

Question 4

A resistor develops heat at the rate of 20 W when the potential difference across its ends is 30 V. The resistance of the resistor is approximately

Accepted Answer

A)  45 $\Omega$ 
B)  5.5 $\Omega$ 
C)  30 $\Omega$ 
D)  13 $\Omega$ 
E)  2 $\Omega$ 
A)  45 $\Omega$ 
B)  5.5 $\Omega$ 
C)  30 $\Omega$ 
D)  13 $\Omega$ 
E)  2 $\Omega$

Question 5

In your four years at college you dry your hair everyday for 5 minutes with a 1200-W hairdryer. If the average price of electrical energy was $0.085 per kilowatt-hour, how much did it cost you during this time? (Assume 1 year = 365 days.)

Accepted Answer

A)  $4.10 
B)  $8.90 
C)  $12.4 
D)  $22.8 
E)  $15.6 
A)  $4.10 
B)  $8.90 
C)  $12.4 
D)  $22.8 
E)  $15.6

Question 6

Lea charges a capacitor and then discharges it through a resistor. She notices that, after three time constants, the voltage across the capacitor has decreased to _____ of its value just prior to the initiation of the discharge.

Accepted Answer

A)  0.368 
B)  0.135 
C)  0.0498 
D)  0.0183 
E)  0.00674 
A)  0.368 
B)  0.135 
C)  0.0498 
D)  0.0183 
E)  0.00674

Question 7

The curve that best illustrates the relation between the current in a metallic conductor and the potential difference between its terminals is

Accepted Answer

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

Question 8

The power dissipated in the unknown resistor (R) is

Accepted Answer

A)  4 W 
B)  6 W 
C)  8 W 
D)  2 W 
E)  10 W 
A)  4 W 
B)  6 W 
C)  8 W 
D)  2 W 
E)  10 W

Question 9

In the above circuit, $\varepsilon$1 = 9 V, $\varepsilon$2 = 6 V, and $\varepsilon$3 = 6 V. Also R1 = 25 $\Omega$, R2 = 125$\Omega$, and R3 = 55$\Omega$. Find the current flowing through R1.

Accepted Answer

A)  0.60 A 
B)  0.072 A 
C)  0.68 A 
D)  0.044 A 
E)  0.16 A 
A)  0.60 A 
B)  0.072 A 
C)  0.68 A 
D)  0.044 A 
E)  0.16 A

Question 10

A wire of length L = 6.0 m has a uniform diameter d = 3.0 mm. When an electric field of E = 0.25 V/m is applied to the wire, the current is 1.5 A. The resistivity of the wire is

Accepted Answer

A)  1.18 *10-6  $\Omega$ .m 
B)  3.53 *10-6  $\Omega$ .m 
C)  2.81 * 10-7  $\Omega$ .m 
D)  7.03 *10-8  $\Omega$ .m 
E)  2.21 * 10-7  $\Omega$ .m 
A)  1.18 *10-6  $\Omega$ .m 
B)  3.53 *10-6  $\Omega$ .m 
C)  2.81 * 10-7  $\Omega$ .m 
D)  7.03 *10-8  $\Omega$ .m 
E)  2.21 * 10-7  $\Omega$ .m

Question 11

The graph shows the potential difference across a resistor as a function of the current through the resistor. The slope of the resulting curve represents

Accepted Answer

A)  power. 
B)  resistance. 
C)  emf. 
D)  charge. 
E)  work per unit charge. 
A)  power. 
B)  resistance. 
C)  emf. 
D)  charge. 
E)  work per unit charge.

Question 12

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. What is the number of protons per unit volume in this beam?

Accepted Answer

A)  3.64 *1013 protons/m3  
B)  2.76 *1013 protons/m3  
C)  1.27 * 1013 protons/m3  
D)  5.98* 1013 protons/m3  
E)  4.17 * 1013 protons/m3  
A)  3.64 *1013 protons/m3  
B)  2.76 *1013 protons/m3  
C)  1.27 * 1013 protons/m3  
D)  5.98* 1013 protons/m3  
E)  4.17 * 1013 protons/m3

Question 13

The current through the battery in the figure is approximately

Accepted Answer

A)  10 A 
B)  13 A 
C)  0.67 A 
D)  6.0 A 
E)  None of these is correct. 
A)  10 A 
B)  13 A 
C)  0.67 A 
D)  6.0 A 
E)  None of these is correct.

Question 14

If 4.0 * 1018 electrons and 1.5 * 1018 protons move in opposite directions past a given cross section of a hydrogen discharge tube every second, the average current in the tube is

Accepted Answer

A)  0.40 A 
B)  0.56 A 
C)  0.88 A 
D)  1.5 A 
E)  4.0 A 
A)  0.40 A 
B)  0.56 A 
C)  0.88 A 
D)  1.5 A 
E)  4.0 A

Question 15

An immersion heater of negligible mass draws a current of 7.5 A from a source with a potential difference of 120 V. The heater is in 0.950 m3 of water. The initial temperature of the water is 12.5ºC. How much time does it take to increase the temperature of the water to 27.5ºC? Neglect any heat loss. One calorie is equivalent to 4.18 J.

Accepted Answer

A)  4.7 *104 s 
B)  3.3 * 104 s 
C)  1.1 * 104 s 
D)  1.6 *104 s 
E)  None of these is correct. 
A)  4.7 *104 s 
B)  3.3 * 104 s 
C)  1.1 * 104 s 
D)  1.6 *104 s 
E)  None of these is correct.

Question 16

A wire 10 m long with a diameter of 1.0 mm has a resistance of 5.0$\Omega$. The resistance of a second wire made of the same material, but 3.0 m long with a diameter of 4.0 mm, is approximately

Accepted Answer

A)  0.38 $\Omega$ 
B)  0.094 $\Omega$ 
C)  0.75 $\Omega$ 
D)  1.7 $\Omega$ 
E)  0.27 k$\Omega$ 
A)  0.38 $\Omega$ 
B)  0.094 $\Omega$ 
C)  0.75 $\Omega$ 
D)  1.7 $\Omega$ 
E)  0.27 k$\Omega$

Question 17

A motor running from a 220-V line is lifting a mass of 35 kg against Earth's gravity at a constant speed of 6.0 m/s. If we assume 100% efficiency, the current required is

Accepted Answer

A)  0.27 A 
B)  9.4 A 
C)  7.7 A 
D)  3.3 A 
E)  4.7 A 
A)  0.27 A 
B)  9.4 A 
C)  7.7 A 
D)  3.3 A 
E)  4.7 A

Question 18

The curve that best represents the current in a discharging RC circuit as a function of time is

Accepted Answer

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

Question 19

The power dissipated in each of two resistors is the same. The potential drop across resistor A is twice that across resistor B. If the resistance of resistor B is R, what is the resistance of A?

Accepted Answer

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

Question 20

Wire A, which is of the same material and cross-sectional area as wire B, is twice as long as wire B. If the resistance of wire B is R, what is the resistance of wire A?

Accepted Answer

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

$The power dissipated in the 21- \Omega resistor in this circuit is$ The power dissipated in the 21- $\Omega$ resistor in this circuit is

Two pieces of copper wire have the same length, but wire A has a square cross section of width s whereas wire B has a circular cross section of diameter s. Which of the following statements is true?

A resistor develops heat at the rate of 20 W when the potential difference across its ends is 30 V. The resistance of the resistor is approximately

In your four years at college you dry your hair everyday for 5 minutes with a 1200-W hairdryer. If the average price of electrical energy was $0.085 per kilowatt-hour, how much did it cost you during this time? (Assume 1 year = 365 days.)

Lea charges a capacitor and then discharges it through a resistor. She notices that, after three time constants, the voltage across the capacitor has decreased to _____ of its value just prior to the initiation of the discharge.

The curve that best illustrates the relation between the current in a metallic conductor and the potential difference between its terminals is

The power dissipated in the unknown resistor (R) is

A wire of length L = 6.0 m has a uniform diameter d = 3.0 mm. When an electric field of E = 0.25 V/m is applied to the wire, the current is 1.5 A. The resistivity of the wire is

The graph shows the potential difference across a resistor as a function of the current through the resistor. The slope of the resulting curve represents

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. What is the number of protons per unit volume in this beam?

The current through the battery in the figure is approximately

If 4.0 * 10¹⁸ electrons and 1.5 * 10¹⁸ protons move in opposite directions past a given cross section of a hydrogen discharge tube every second, the average current in the tube is

A wire 10 m long with a diameter of 1.0 mm has a resistance of 5.0 $\Omega$ . The resistance of a second wire made of the same material, but 3.0 m long with a diameter of 4.0 mm, is approximately

A motor running from a 220-V line is lifting a mass of 35 kg against Earth's gravity at a constant speed of 6.0 m/s. If we assume 100% efficiency, the current required is

The curve that best represents the current in a discharging RC circuit as a function of time is

The power dissipated in each of two resistors is the same. The potential drop across resistor A is twice that across resistor B. If the resistance of resistor B is R, what is the resistance of A?

Wire A, which is of the same material and cross-sectional area as wire B, is twice as long as wire B. If the resistance of wire B is R, what is the resistance of wire A?

The Electric Field I: Discrete Charge Distributions

The Electric Field II: Continuous Charge Distributions

Electric Potential

Capacitance

The Magnetic Field

Sources of the Magnetic Field

Magnetic Induction

Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

Interference and Diffraction

Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

Atoms

Molecules

Solids and the Theory of Conduction

Relativity

Nuclear Physics

Elementary Particles and the Beginning of the Universe

Filters

Exam 5: Electric Current and Direct-Current Circuits

The power dissipated in the 21- Ω\OmegaΩ resistor in this circuit is

Two pieces of copper wire have the same length, but wire A has a square cross section of width s whereas wire B has a circular cross section of diameter s. Which of the following statements is true?

In the diagram above, the voltage difference between a and b is 6 V. If R1 = 25 Ω\OmegaΩ , R3 = 45 Ω\OmegaΩ , and I = 0.095 A, then find the current flowing through R2.

A resistor develops heat at the rate of 20 W when the potential difference across its ends is 30 V. The resistance of the resistor is approximately

In your four years at college you dry your hair everyday for 5 minutes with a 1200-W hairdryer. If the average price of electrical energy was $0.085 per kilowatt-hour, how much did it cost you during this time? (Assume 1 year = 365 days.)

Lea charges a capacitor and then discharges it through a resistor. She notices that, after three time constants, the voltage across the capacitor has decreased to _____ of its value just prior to the initiation of the discharge.

The curve that best illustrates the relation between the current in a metallic conductor and the potential difference between its terminals is

The power dissipated in the unknown resistor (R) is

In the above circuit, ε\varepsilonε 1 = 9 V, ε\varepsilonε 2 = 6 V, and ε\varepsilonε 3 = 6 V. Also R1 = 25 Ω\OmegaΩ , R2 = 125 Ω\OmegaΩ , and R3 = 55 Ω\OmegaΩ . Find the current flowing through R1.

A wire of length L = 6.0 m has a uniform diameter d = 3.0 mm. When an electric field of E = 0.25 V/m is applied to the wire, the current is 1.5 A. The resistivity of the wire is

The graph shows the potential difference across a resistor as a function of the current through the resistor. The slope of the resulting curve represents

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. What is the number of protons per unit volume in this beam?

The current through the battery in the figure is approximately

If 4.0 * 1018 electrons and 1.5 * 1018 protons move in opposite directions past a given cross section of a hydrogen discharge tube every second, the average current in the tube is

A wire 10 m long with a diameter of 1.0 mm has a resistance of 5.0 Ω\OmegaΩ . The resistance of a second wire made of the same material, but 3.0 m long with a diameter of 4.0 mm, is approximately

A motor running from a 220-V line is lifting a mass of 35 kg against Earth's gravity at a constant speed of 6.0 m/s. If we assume 100% efficiency, the current required is

The curve that best represents the current in a discharging RC circuit as a function of time is

The power dissipated in each of two resistors is the same. The potential drop across resistor A is twice that across resistor B. If the resistance of resistor B is R, what is the resistance of A?

Wire A, which is of the same material and cross-sectional area as wire B, is twice as long as wire B. If the resistance of wire B is R, what is the resistance of wire A?

The Electric Field I: Discrete Charge Distributions

The Electric Field II: Continuous Charge Distributions

Electric Potential

Capacitance

The Magnetic Field

Sources of the Magnetic Field

Magnetic Induction

Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

Interference and Diffraction

Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

Atoms

Molecules

Solids and the Theory of Conduction

Relativity

Nuclear Physics

Elementary Particles and the Beginning of the Universe

Filters

$The power dissipated in the 21- \Omega resistor in this circuit is$ The power dissipated in the 21- $\Omega$ resistor in this circuit is

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. What is the number of protons per unit volume in this beam?

If 4.0 * 10¹⁸ electrons and 1.5 * 10¹⁸ protons move in opposite directions past a given cross section of a hydrogen discharge tube every second, the average current in the tube is

A wire 10 m long with a diameter of 1.0 mm has a resistance of 5.0 $\Omega$ . The resistance of a second wire made of the same material, but 3.0 m long with a diameter of 4.0 mm, is approximately