Abington Heights High School
Physics
Practice Quiz Chapter 20 - Quiz 3
1.

A circuit is pulled with a 16-N force toward the right to maintain a constant speed v. At the instant shown, the loop is partially in and partially out of a uniform magnetic field that is directed into the paper. As the circuit moves, a 6.0-A current flows through a 4.0-W resistor.


R-1 Ref 22-2

Which one of the following statements concerning this situation is true?
A.The temperature of the circuit remains constant.
B.The induced current flows clockwise around the circuit.
C.Since the circuit moves with constant speed, the force F does zero work.
D.If the circuit were replaced with a wooden loop, there would be no induced emf.
E.As the circuit moves through the field, the field does work to produce the current.

2.

A circuit is pulled with a 16-N force toward the right to maintain a constant speed v. At the instant shown, the loop is partially in and partially out of a uniform magnetic field that is directed into the paper. As the circuit moves, a 6.0-A current flows through a 4.0-W resistor.


R-1 Ref 22-2

With what speed does the circuit move?
A.1.5 m/s
B.3.0 m/s
C.6.4 m/s
D.9.0 m/s
E.12 m/s

3. A circular coil has 275 turns and a radius of 0.045 m. The coil is used as an ac generator by rotating it in a 0.500 T magnetic field, as shown in the figure. At what angular speed should the coil be rotated so that the maximum emf is 175 V?.

A.28 rad/s
B.50 rad/s
C.130 rad/s
D.200 rad/s
E.490 rad/s
4. The angular speed of a motor is 262 rad/s. The back emf generated by the motor is 89.4 V. Assuming all other factors remain the same, determine the back emf if the angular speed of the motor is reduced to 154 rad/s.
A.32.3 V
B.44.7 V
C.52.5 V
D.89.4 V
E.152 V
5.
A single conducting loop with an area of 2.0 m2 rotates in a uniform magnetic field so that the induced emf has a sinusoidal time dependence as shown.
R-2 Ref 22-3

Determine the strength of the magnetic field in which the loop rotates.
A.0.5 T
B.2.4 T
C.3.0 T
D.7.5 T
E.18.8 T

6.
A single conducting loop with an area of 2.0 m2 rotates in a uniform magnetic field so that the induced emf has a sinusoidal time dependence as shown.
R-2 Ref 22-3

With what angular frequency does the loop rotate?
A.0.16 rad/s
B.0.30 rad/s
C.0.52 rad/s
D.0.80 rad/s
E.1.26 rad/s

7.
A single conducting loop with an area of 2.0 m2 rotates in a uniform magnetic field so that the induced emf has a sinusoidal time dependence as shown.
R-2 Ref 22-3

What is the period of the induced current?
A.1.25 s
B.2.50 s
C.3.75 s
D.5.00 s
E.6.25 s

8. A closed loop carries a current that increases with time. Which one of the quantities listed below relates the emf induced in the loop to the rate at which the current is increasing?
A.resistance of the loop
B.capacitance of the loop
C.self-inductance of the loop
D.power dissipated by the loop
E.mutual inductance of the loop
9. The current in a solenoid is decreased to one-half of its original value. Which one of the following statements is true concerning the self-inductance of the solenoid?
A.The self-inductance does not change.
B.The self-inductance increases by a factor of two.
C.The self-inductance decreases by a factor of two.
D.The self-inductance increases by a factor of four.
E.The self-inductance decreases by a factor of four.
10. Determine the energy stored in a 95-mH inductor that carries a 1.4-A current.
A.0.38 J
B.0.27 J
C.0.19 J
D.0.093 J
E.0.066 J
11. A solenoid with 1000 turns has a cross-sectional area of 7.0 cm2 and length of 25 cm. How much energy is stored in the magnetic field of the solenoid when it carries a current of 10.0 A?
A.0.10 J
B.2.8 J
C.0.18 J
D.28 J
E.0.36 J
12. Which one of the following combinations of units is equivalent to one henry?
A.N • m • s/C
B.N • m • s2/C
C.N • m • C2/s2
D.N • m • C/s2
E.N • m • s2/C2

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