Electric Circuits Practice Test 2

1.

In a circuit, a 24 V battery is connected to three resistors: 2 Ω and 4 Ω in series, and this combination in parallel with a 6 Ω resistor. What is the total current supplied by the battery?

a) 2.0 A b) 3.0 A c) 4.0 A d) 6.0 A

2.

In a multi-loop circuit, a 12 V battery is in loop 1 with a 3 Ω resistor, and loop 2 has a 6 V battery and a 6 Ω resistor. The loops share a 2 Ω resistor. If the current through the shared resistor is 1 A from loop 1 to loop 2, what is the current in the 3 Ω resistor?

a) 0.5 A b) 1.0 A c) 1.5 A d) 2.0 A

3.

In a circuit, a 24 V battery is connected to a 4 Ω resistor and a 12 Ω resistor in parallel. What is the voltage across the 12 Ω resistor?

a) 6 V b) 8 V c) 12 V d) 24 V

4.

Derivation: Show that the maximum power delivered to a load resistor R_L from a battery with emf E and internal resistance r occurs when R_L = r. What is the maximum power?

a) E²/2r b) E²/4r c) E²/r d) E²/8r

5.

In a circuit, a 10 μF capacitor is charged to 50 V and then disconnected and connected across a 1 kΩ resistor. How long does it take for the voltage to drop to 10 V?

a) 11 ms b) 23 ms c) 46 ms d) 69 ms

6.

Which of the following best describes the effect of inserting a dielectric with constant k between the plates of a charged, isolated capacitor?

a) Capacitance increases, voltage increases b) Capacitance increases, voltage decreases c) Capacitance decreases, voltage increases d) Capacitance decreases, voltage decreases

7.

In a circuit, a 5 Ω resistor and a 10 Ω resistor are connected in parallel to a 20 V battery. What is the total power dissipated in the circuit?

a) 40 W b) 60 W c) 80 W d) 100 W

8.

Derivation: For a charging RC circuit, derive the expression for the charge on the capacitor as a function of time.

a) Q(t) = Q₀(1 - e^{-t/RC}) b) Q(t) = Q₀e^{-t/RC} c) Q(t) = Q₀e^{t/RC} d) Q(t) = Q₀(1 + e^{-t/RC})

9.

In a circuit, a 12 V battery is connected to a 3 Ω resistor and a 6 Ω resistor in parallel. What is the current through the 6 Ω resistor?

a) 1.0 A b) 1.5 A c) 2.0 A d) 4.0 A

10.

Which of the following best describes the effect of increasing the area of the plates of a parallel-plate capacitor (with fixed separation and dielectric)?

a) Capacitance increases b) Capacitance decreases c) Capacitance is unchanged d) Capacitance becomes zero

11.

At a junction, 2 A flows in, 1.5 A flows out, and 0.3 A flows in. What is the magnitude and direction of the remaining current?

a) 0.2 A in b) 0.2 A out c) 0.8 A in d) 0.8 A out

12.

In a circuit, a 24 V battery is connected to a 6 Ω resistor and a 12 Ω resistor in series. What is the voltage drop across the 12 Ω resistor?

a) 6 V b) 8 V c) 12 V d) 16 V

13.

Derivation: For two resistors R1 and R2 in parallel, what is the equivalent resistance?

a) R1 + R2 b) (R1 × R2)/(R1 + R2) c) R1 - R2 d) (R1 + R2)/2

14.

In a circuit, a 10 Ω resistor and a 20 Ω resistor are connected in series to a 30 V battery. What is the power dissipated in the 20 Ω resistor?

a) 10 W b) 15 W c) 20 W d) 30 W

15.

In a circuit, a 5 μF capacitor is charged to 100 V and then discharged through a 2 kΩ resistor. What is the current through the resistor 1 ms after discharge begins?

a) 0.018 mA b) 0.27 mA c) 0.37 mA d) 0.50 mA

16.

Which of the following best describes the effect of adding a capacitor in parallel to an existing capacitor in a circuit?

a) Increases total capacitance b) Decreases total capacitance c) Has no effect on total capacitance d) Increases total voltage

17.

In a circuit, a 6 V battery is connected to a 2 Ω resistor and a 4 Ω resistor in parallel. What is the power dissipated in the 4 Ω resistor?

a) 1.5 W b) 3.0 W c) 6.0 W d) 9.0 W

18.

What is the time constant for an RC circuit with a 2 kΩ resistor and a 10 μF capacitor?

a) 0.02 s b) 0.2 s c) 2.0 s d) 20 s

19.

In a multi-loop circuit, a 15 V battery is in loop 1 with a 5 Ω resistor, and loop 2 has a 10 V battery and a 10 Ω resistor. The loops share a 2 Ω resistor. If the current through the shared resistor is 1 A from loop 1 to loop 2, what is the current in the 5 Ω resistor?

a) 1.0 A b) 2.0 A c) 3.0 A d) 4.0 A

20.

What is the time constant for an RC circuit with a 500 Ω resistor and a 40 μF capacitor?

a) 0.02 s b) 0.04 s c) 0.2 s d) 2.0 s

21.

At a junction, 3 A enters, 2 A leaves, and 1 A enters. What is the value and direction of the remaining current?

a) 0 A entering b) 0 A leaving c) 2 A entering d) 2 A leaving

22.

What is the equivalent resistance of two resistors, 5 Ω and 10 Ω, connected in parallel?

a) 2.5 Ω b) 3.3 Ω c) 5.0 Ω d) 15.0 Ω

23.

In a multi-loop circuit, a 15 V battery is in loop 1 with a 5 Ω resistor, and loop 2 has a 10 V battery and a 10 Ω resistor. The loops share a 2 Ω resistor. If the current through the shared resistor is 1 A from loop 1 to loop 2, what is the current in the 5 Ω resistor?

a) 1.0 A b) 2.0 A c) 3.0 A d) 4.0 A

24.

What is the energy stored in a 10 μF capacitor charged to 50 V?

a) 0.0125 J b) 0.025 J c) 0.050 J d) 0.10 J

25.

Which of the following best describes the effect of adding a capacitor in series to an existing capacitor in a circuit?

a) Increases total capacitance b) Decreases total capacitance c) Has no effect on total capacitance d) Increases total voltage

26.

In a circuit, a 20 V battery is connected to a 2 Ω resistor and a 3 Ω resistor in parallel. What is the total current supplied by the battery?

a) 5.0 A b) 10.0 A c) 13.3 A d) 20.0 A

27.

What is the energy stored in a 50 μF capacitor charged to 100 V?

a) 0.25 J b) 0.5 J c) 1.0 J d) 2.5 J

28.

Which of the following best describes the effect of adding a resistor in series to an existing resistor in a circuit?

a) Increases total resistance b) Decreases total resistance c) Has no effect on total resistance d) Increases total voltage

29.

In a multi-loop circuit, a 20 V battery is in loop 1 with a 4 Ω resistor, and loop 2 has a 10 V battery and a 2 Ω resistor. The loops share a 2 Ω resistor. If the current through the shared resistor is 1 A from loop 1 to loop 2, what is the current in the 4 Ω resistor?

a) 1.0 A b) 2.0 A c) 3.0 A d) 4.0 A

30.

Which of the following best describes the effect of connecting a real (non-ideal) voltmeter across a resistor in a circuit?

a) It draws no current and does not affect the circuit b) It draws a small current, slightly reducing the measured voltage c) It increases the current through the resistor d) It shorts the resistor

Electric Circuits Practice Test 2

30 New Challenging Questions – AP Physics C Level