Basic Electrical MCQ #19

1) What is the phase difference between voltage and current, if AC circuit consist only resistance?

      (a) 45º

      (b) Zero

      (c) 90º

      (d) 270º

2) What is the phase difference between voltage and current, if AC circuit consist of purely inductive load?

      (a) 45º

      (b) Zero

      (c) 90º

      (d) 270º

3) What is the power factor of AC circuit with purely inductive load?

      (a) leading

      (b) lagging

      (c) unity

      (d) fluctuate between leading and lagging

4) Impedance of purely inductive circuit is expressed by______.

      (a) Z = R + j XC

      (b) Z = j XL

      (c) Z = R

      (d) Z = j XL + R

ANSWER: | 1-B | 2-C | 3-B | 4-B |

5) what is the phase difference between the voltage and current of ac circuit consist only capacitor?

      (a) 45º

      (b) Zero

      (c) 90º

      (d) 270º

6) In a purely capacitive circuit current ______ voltage by _______

      (a) lags, 90

      (b) leads, 90

      (c) in phase

      (d) out of phase

7) Which of the following represent ohm’s law for purely capacitive circuit?

      (a) V = I Xc

      (b) V = I Xl

      (c) V = I

      (d) Xc = I/V

8) In purely capacitive circuit, the resistive part is ______

      (a) infinite

      (b) finite

      (c) unity

      (d) zero

ANSWER: | 5-C | 6-B | 7-A | 8-D |

9) What is the unit of impedance (Z)?

      (a) Weber per meter

      (b) Henry per meter

      (c) ohm per meter

      (d) ohm

10) What is unit of susceptance?

      (a) Siemens

      (b) ohms

      (c) Henry

      (d) Farad

11) Find voltage across R and L if a series circuit of R= 20 ohms and L = 20 mH and supply is 60 V with 100 Hs.

      (a) 31.9 V and 50.8 V

      (b) 5.08 V and 3.19 V

      (c) 50.8 V and 31.9 V

      (d) 51.8 V and 32.9 V

12) which of the following is reciprocal of impedance?

      (a) capacitance

      (b) Admittance

      (c) inductance

      (d) reactance

ANSWER: | 9-D | 10-A | 11-C | 12-B |