LR, RC and LCR Circuits

Practice Questions:

Question 11: easy

In series LCR circuit voltage across L, C & R is 20V each. If capacitor is short-circuited then
voltage across inductor is :

1. 20 V

2. 20√2 V

3. 10√2 V

4. 10 V

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Question 12: moderate

Which of the following plot correctly depicts the variation of phase difference between voltage and current in a series L-C AC circuit ?

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Question 13: moderate

When S1 is closed and S2 is open, \[V_{L}=V_{R}=V_{C}=10V\]. What will be the value of

\[V_{C}\] if S1 opened and S2 is closed ?

1. 10

2. 10√2

3. 10/√2

4. 15√2

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Question 14: easy

A variable inductor is connected to an ac source. What effect does increasing the inductance have on the reactance and current in this circuit ?

1. Reactance - Decreases, Current - No change

2. Reactance - Increases, Current - Increases

3. Reactance - Decreases, Current - Increases

4. Reactance - Increases, Current - Decreases

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Question 15: easy

A variable capacitor is connected to an ac source. What effect does decreasing the capacitance have on the reactance and current in this circuit ?

1. Reactance - Decreases, Current - No change

2. Reactance - Increases, Current - Increases

3. Reactance - Decreases, Current -Increases

4. Reactance - Increases, Current -Decreases

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Question 16: moderate

In the circuit of Figure, the volmeter reads 75 V.Value of C is :

1. 4 μF

2. 2 μF

3. 6 μF

4. 10 μF

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