Power Quality and Management (2180911) MCQs

MCQs of Power Factor

Showing 1 to 10 out of 29 Questions
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1.
Which one of the following loads has the poorest power factor?
(a) Electric fan Induction motor
(b) Transformer
(c) Induction motor
(d) Induction furnace
Answer:

Option (d)

2.
Which one is NOT the cause of the decrease in power factor?
(a) Decrease in system voltage.
(b) Increase in air gap in induction motor.
(c) Operating equipment at part load
(d) Operating synchronous motor with over excitation
Answer:

Option (d)

3.
Which one of the following statements is NOT true?
(a) When the equipment is designed at low power factor it is to be designed for more kVA
(b) When power factor is decreased, loss in the cable supplying load is decreased.
(c) Due to reduced power factor voltage regulation of line becomes poor
(d) Reduced power factor reduces the efficiency of the plant
Answer:

Option (b)

4.
Which one of the following statements is NOT true regarding use of capacitor for power factor correction ?
(a) Capacitor should be connected near the supply.
(b) Protection fuse should be connected in the line of the capacitor bank.
(c) Capacitors should be switched off during off-peak period
(d) Switching current of capacitor is more so its wire should be of sufficient size
Answer:

Option (b)

5.
Which one of the following statements is NOT true for the capacitors used for power factor improvement ?
(a) Enclosure of capacitor bank should be earthed.
(b) Capacitor bank is used up to 100 kVAr.
(c) Capacitor should be connected near the load
(d) Capacitor once switched off, a minimum period of one minute should be allowed before switching on again
Answer:

Option (b)

6.
Which one of the following statements is NOT true for synchronous motor used for power factor improvement in comparison with static condenser
(a) Its maintenance is more
(b) It operates at zero leading power factor only
(c) It requires D. C. supply
(d) It requires more space
Answer:

Option (c)

7.
Which one of the following is NOT true for capacitor in comparison with synchronous motor for power factor improvement?
(a) Required power factor can be adjusted accurately
(b) It does not require d. c. supply
(c) It occupies less space
(d) Its maintenance is less
Answer:

Option (a)

8.
Which one of the following statements is NOT true for capacitor used for improvement of power factor?
(a) Current drawn by the capacitor leads the supply voltage by 90°
(b) Load current decreases
(c) Current taken from the supply decreases
(d) Load power remains constant
Answer:

Option (b)

9.
Component of current in phase with the voltage is called component
(a) Apparent
(b) Quadrature
(c) Active
(d) Reactive
Answer:

Option (c)

10.
Power factor can be mathematically expressed as:
(a) P/Q
(b) Q/P
(c) P/S
(d) S/P
Answer:

Option (c)

Showing 1 to 10 out of 29 Questions
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