# Practice Test: Question Set - 05

**1. The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is**

- (A) 4 kVAR

- (B) 6 kVAR

- (C) 8 kVAR

- (D) 16 kVAR

**2. In a sine wave the slope is constant**

- (A) Between 0° and 90°

- (B) Between 90° and 180°

- (C) Between 180° and 270°

- (D) No where

**3. The r.m.s. value of pure cosine function is**

- (A) 0.5 of peak value

- (B) 0.707 of peak value

- (C) Same as peak value

- (D) Zero

**4. In a pure capacitive circuit if the supply frequency is reduced to 1/2, the current will**

- (A) Be reduced by half

- (B) Be doubled

- (C) Be four times at high

- (D) Be reduced to one fourth

**5. Capacitors for power factor correction are rated in**

- (A) kW

- (B) kVA

- (C) kV

- (D) kVAR

**6. The reactance offered by a capacitor to alternating current of frequency 50 Hz is 20 Q. If frequency is increased to 100 Hz, reactance becomes __________ ohms.**

- (A) 2.5

- (B) 5

- (C) 10

- (D) 15

**7. For the same peak value which of the following wave will 'have the highest r.m.s. value?**

- (A) Square wave

- (B) Half wave rectified sine wave

- (C) Triangular wave

- (D) Sine wave

**8. The r.m.s. value of a sinusoidal A.C. current is equal to its value at an angle of ________ degrees.**

- (A) 90

- (B) 60

- (C) 45

- (D) 30

**9. Power factor of an inductive circuit is usually improved by connecting capacitor to it in**

- (A) Parallel

- (B) Series

- (C) Either (A) or (B)

- (D) None of the above

**10. In the case of an unsymmetrical alternating current the average value must always be taken over**

- (A) Unsymmetrical part of the wave form

- (B) The quarter cycle

- (C) The half cycle

- (D) The whole cycle

**View All Answers**

## 0 blogger:

## Post a Comment