Alternating Current Class 12 MCQs Questions with Answers

1. In an L.C.R. series a.c. circuit, the current

2. Consider the following statements and then select the correct statements.
I. Most of the electrical device we use require AC voltage.
II. Most of the electrical energy sold by power companies is transmitted and distributed as alternating current.
III. AC voltage can be easily and efficiently converted from one to the other by means of transformers.

3. The dimensional formula of impedance is;

4. For minimum dissipation of energy in the circuit the power factor should be

5. Which of the following effects is not shown in alternating current ?

6.  
A rejector circuit is:

7. The transformation ratio in the step-up transformer is

8. Transformer works on the principle of:

9. A rejector circuit is:

10. A bulb connected in series with a solenoid is lit by an AC source. If a soft iron core is introduced in the solenoid then,

11.  
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?

12. A capacitor has capacitance C and reactance X, if capacitance and frequency become double, then reactance will be

13.  
Identify the principle behind the working of an a.c. generator.

14. Power factor of an ac circuit is a measure of:

15. Alternating current can not be measured by D.C. ammeter, because

16. Quantity that remains unchanged in a transformer is

17. An AC voltage source of variable angular frequency ω and fixed amplitude V0 is connected in series with a capacitance C and an electric bulb of resistance R (inductance zero). When ω is increased then,

18. In parallel resonant circuit:

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

20. Power factor is one for