 # Class 12 Physics Chapter 7 Alternating Current MCQs

Get your hand on the latest Class 12 Physics MCQs for Chapter 7 Alternating Current, along with their answers. The MCQs with answers for Class 12 Physics are provided as per the latest exam pattern. Going through these questions will help students improve their critical thinking abilities and help them score good marks in board exams.

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## Class 12 Alternating Current MCQs

Check the multiple-choice questions for the 12th Class Physics Alternating Current chapter. Each MCQ will have four options here, out of which only one is correct. Students have to pick the correct option and check the answer provided here.

1. What is the frequency of the AC Mains in India?

1. 60 Hz
2. 50 Hz
3. 40 Hz
4. 30 Hz

Explanation: The frequency of the AC Mains in India is 50 Hz.

2. An alternating current can be produced by a

1. Choke Coil
2. Dynamo
3. Electric Motor
4. Transformer

Explanation: An alternating current can be produced by a dynamo.

3. Which of the following can measure an alternating current?

1. Voltmeter
2. Ammeter
3. Suspended coil Galvanometer
4. Moving Coil Galvanometer

Explanation: Ammeter can measure an alternating current.

4. Which of the following circuits exhibits maximum power dissipation?

1. Pure Inductive Circuit
2. Pure Capacitive Circuit
3. Pure Resistive Circuit
4. None of the above

Explanation: A pure resistive circuit exhibits maximum power dissipation.

5. What happens to the inductive reactance when the frequency of the AC supply is increased?

1. Increases
2. Decreases
3. Remains the same
4. Decreases inversely

Explanation: The inductive reactance of the AC supply increases with the frequency of the AC supply.

6. What happens to the quality factor of an LCR circuit if the resistance is increased?

1. Increases
2. Decreases
3. Remains the same
4. None of the above

Explanation: The quality factor of an LCR circuit decreases if the resistance of the circuit is increased.

7. Which of the following statements is true about the LCR circuit connected to an AC source at resonance?

1. R equals the applied voltage.
2. R is zero
3. C is zero
4. L equals the applied voltage

Answer: (a) R equals the applied voltage.

Explanation: At resonance, R equals the applied voltage.

8. The impedance in the series LCR circuit is minimum at the resonance frequency.

1. True
2. False

Explanation: The impedance in the series LCR circuit is minimum at the resonance frequency.

9. When is the current in a circuit wattless?

1. When the inductance of the circuit is zero.
2. When the resistance of the circuit is zero.
3. When the current is alternating
4. When both resistance and inductance is zero

Answer: (b) When the resistance of the circuit is zero.

Explanation: The current in a circuit is wattless when the resistance of the circuit is zero.

10. The power factor is one for which of the following?

1. Pure capacitor
2. Pure inductor
3. Pure resistor
4. All of the above