R4RIN – MCQs, Mock Tests | CBES Board Class 12 CBES Board(Class 12-Physics)MCQ Questions with Answers(Chapter 7 Alternating Current)

In a pure capacitive circuit if the frequency of ac source is doubled, then its capacitive reactance will be

1. remains same
2. zero
3. doubled
4. halved

✅ Correct Answer: 3

In an alternating current circuit consisting of elements in series, the current increases on increasing the frequency of supply. Which of the following elements are likely to constitute the circuit?

1. Only resistor
2. Resistor and inductor
3. Resistor and capacitor
4. Only inductor

✅ Correct Answer: 3

In which of the following circuits the maximum power dissipation is observed?

1. Pure capacitive circuit
2. Pure inductive circuit
3. Pure resistive circuit
4. None of these

✅ Correct Answer: 3

In a series LCR circuit the voltage across an inductor, capacitor and resistor are 20 V, 20 V and 40 V respectively. The phase difference between the applied voltage and the current in the circuit is

1. 30°
2. 45°
3. 60°
4. 0°

✅ Correct Answer: 4

At resonance frequency the impedance in series LCR circuit is

1. maximum
2. minimum
3. zero
4. infinity

✅ Correct Answer: 2

At resonant frequency the current amplitude in series LCR circuit is

1. maximum
2. minimum
3. zero
4. infinity

✅ Correct Answer: 1

Quality factor and power factor both have the dimensions of

1. time
2. frequency
3. work
4. angle

✅ Correct Answer: 4

A transformer works on the principle of

1. self induction
2. electrical inertia
3. mutual induction
4. magnetic effect of the electrical current

✅ Correct Answer: 3

For an ideal-step-down transformer, the quantity which is constant for both the coils is

1. current in the coils
2. voltage across the coils
3. resistance of coils
4. power in the coils

✅ Correct Answer: 4