Alternating Current MCQs
1. If a secondary coil has 40 turns, and, a primary coil with 20 turns is charged with 50 V of potential difference, then the potential difference in the secondary coil would be
A. 50 V in secondary coil
B. 25 V in secondary coil
C. 60 V in secondary coil
D. 100 V in secondary coil
2. Generators at a power station produce electric power at voltage
A. 45 kW
B. 50 kW
C. 60 kW
D. 25 kW
3. Equation which measures alternating voltage is
A. Vsin ω
B. sin t
C. Vo sinωt
D. V=IR
4. In transformer, alternating current is induced in
A. primary coil
B. secondary coil
C. iron core
D. resistor
5. High voltages lead to
A. less power loss
B. more power loss
C. high current
D. high resistance
6. Graph of alternating current is a
A. cos wave
B. tan wave
C. curve
D. sine wave
7. A component that allows only unidirectional current to pass through it is
A. resistor
B. inductor
C. transformer
D. diode
8. Average power dissipated in resistor if sinusoidal p.d of peak value 25V is connected across a 20 Ω resistor is
A. 15.6 W
B. 15 W
C. 16 W
D. 17 W
9. Amount of d.c voltage as compare to Vo is
A. 50%
B. 60%
C. 70%
D. 80%
10. A well designed transformer loses power under
A. 10%
B. 1.20%
C. 0.1%
D. 20%
11. Ratio of voltages is equal to ratio of
A. iron sheets in core
B. coil
C. number of turns in coil
D. all of above
12. Process in which A.C is converted into D.C is called
A. induction
B. rectification
C. inversion
D. dispersion
13. Steady d.c voltage is also known as
A. square velocity
B. root mean square velocity
C. root velocity
D. velocity
14. Ratio of voltages is inverse ratio of the
A. transformer
B. resistor
C. iron core
D. current
15. If output voltage is greater than input voltage, then transformer is
A. step up
B. step down
C. faulty
D. fatal
16. Highest point on AC graph is known as
A. peak value
B. amplitude
C. frequency
D. wave front