Physics MCQs for CSIR NET JRF Part 2

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Question:

In a step-down transformer, the number of turns in

  1. Primary are less

  2. Primary are more

  3. Primary and secondary equal

  4. Secondary are infinite

Question:

In AC circuits choke is preferred to resistors because.

  1. Choke coil is cheap

  2. Voltage increases

  3. Energy is not wasted

  4. Current increases

Question:

A choke is used as resistance in

  1. AC circuits.

  2. DC circuits.

  3. Half-wave rectifier circuits.

  4. Both AC and DC circuits.

Question:

The frequency of AC mains in India is

Question:

A transformer works on

  1. DC only.

  2. AC only.

  3. Both AC and DC.

  4. High voltage only.

Question:

Alternating voltage

  1. Is independent of time.

  2. Varies directly with time.

  3. Varies inversely with time.

  4. Varies sinusoidally with time.

Question:

The law of electromagnetic induction have been used in the construction of

  1. Electric operator.

  2. Electric motor.

  3. Galvanometer.

  4. None of the above.

Question:

Power consumed in an AC circuit become zero if

  1. Inductance and resistance are both high.

  2. Inductance and resistance are both low.

  3. Inductance very high and resistance negligible.

  4. Inductance low and resistance high.

Question:

The rms value of current is