Applied Electricity

Question 1

1Impedance is measured in

Easy

A. ohms B. farads C. watts D. henrys

Question 2

2The period of a 50 Hz supply is

Hard

A. 0.02 s B. 0.5 s C. 0.2 s D. 50 s

Question 3

3In a purely inductive circuit, current

Medium

A. is in phase with the voltage B. lags the voltage by 90° C. is zero D. leads the voltage by 90°

Question 4

4The power factor of a purely resistive circuit is

Easy

A. 0 B. −1 C. 0.5 D. 1

Question 5

5In an RLC series circuit at resonance, the current is

Hard

A. maximum and in phase with the voltage B. zero C. lagging by 90° D. minimum

Question 6

6The r.m.s. value of a sinusoidal voltage with a peak value of 100 V is about

Medium

A. 100 V B. 70.7 V C. 141 V D. 50 V

Question 7

7The frequency of an a.c. supply with period 0.02 s is

Easy

A. 0.02 Hz B. 500 Hz C. 20 Hz D. 50 Hz

Question 8

8Power factor in an a.c. circuit is

Medium

A. resistance ÷ current B. true power ÷ apparent power C. apparent power ÷ true power D. voltage × current

Question 9

9The r.m.s. value of an a.c. with peak 100 V is about

Hard

A. 100 V B. 70.7 V C. 50 V D. 141 V

Question 10

10In a purely inductive circuit, the current

Medium

A. is in phase with the voltage B. lags the voltage by 90° C. is zero D. leads the voltage by 90°