Practice Test: Question Set - 10
1. The peak value of a sine wave is 200 V. Its average value is
- (A) 127.4 V
- (B) 141.4 V
- (C) 282.8 V
- (D) 200 V
2. The inductance of a coil can be increased by
- (A) Increasing core length
- (B) Decreasing the number of turns
- (C) Decreasing the diameter of the former
- (D) Choosing core material having high relative
permeability
3. For a sine wave with peak value Imax the r.m.s. value is
- (A) 0.5 Imax
- (B) 0.707
- (C) 0.9
- (D) 1.414 Imax
4. For a frequency of 200 Hz, the time period will be
- (A) 0.05 s
- (B) 0.005 s
- (C) 0.0005 s
- (D) 0.5 s
5. The ratio of active power to apparent power is known as factor.
- (A) Demand
- (B) Load
- (C) Power
- (D) Form
6. The best place to install a capacitor is
- (A) Very near to inductive load
- (B) Across the terminals of the inductive load
- (C) Far away from the inductive load
- (D) Any where
7. Inductance of a coil Varies
- (A) Directly as the cross-sectional area of
magnetic core
- (B) Directly as square of number of turns
- (C) Inversely as the length of the iron path
- (D) As (A) to (C)
8. Power factor of the following circuit will be unity
- (A) Inductance
- (B) Capacitance
- (C) Resistance
- (D) Both (A) and (B)
9. The r.m.s. value of alternating current is given by steady (D.C.) current which when flowing through a given circuit for a given time produces
- (A) The more heat than produced by A.C. when flowing
through the same circuit
- (B) The same heat as produced by A.C. when flowing
through the same circuit
- (C) The less heat than produced by A.C. flowing through
the same circuit
- (D) None of the above
10. In a pure resistive circuit
- (A) Current lags behind the voltage by 90°
- (B) Current leads the voltage by 90°
- (C) Current can lead or lag the voltage by 90°
- (D) Current is in phase with the voltage
11. Time constant of a circuit is the time in seconds taken after the application of voltage to each
- (A) 25% of maximum value
- (B) 50% of maximum value
- (C) 63% of maximum value
- (D) 90% of the maximum value
12. What will be the phase angle between two alternating waves of equal frequency, when one wave attains maximum value the other is at zero value?
- (A) 0°
- (B) 45°
- (C) 90°
- (D) 180°
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