21. The phase difference between voltage and current wave through a circuit element is given as 30°. The essential condition is that
(a) both waves must have same frequency
(b) both waves must have identical peak values
(c) both waves must have zero value at the same time
(d) none of the above
Ans: a
22. 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
Ans: c
23. Capacitive reactance is more when
(a) capacitance is less and frequency of supply is less
(b) capacitance is less and frequency of supply is more
(c) capacitance is more and frequency of supply is less
(d) capacitance is more and frequency of supply is more
Ans: a
24. In a series resonant circuit, the impedance of the circuit is
(a) minimum
(b) maximum
(c) zero
(d) none of the above
Ans: a
25. Power factor of an electrical circuit is equal to
(a) R/Z
(b) cosine of phase angle difference between current and voltage
(c) kW/kVA
(d) ratio of useful current to total current Iw/I
(e) all above
Ans: e
26. 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
Ans: b
27. Poor power factor
(a) reduces load handling capability of electrical system
(b) results in more power losses in the electrical system
(c) overloads alternators, transformers and distribution lines
(d) results in more voltage drop in the line
(e) results in all above
Ans: e
28. Capacitors for power factor correction are rated in
(a) kW
(b) kVA
(c) kV
(d) kVAR
Ans: d
29. In series resonant circuit, increasing inductance to its twice value and reducing capacitance to its half value
(a) will change the maximum value of current at resonance
(6) will change the resonance frequency
(c) will change the impedance at resonance frequency
(d) will increase the selectivity of the circuit
Ans: d
30. Pure inductive circuit
(a) consumes some power on average
(b) does not take power at all from a line
(c) takes power from the line during some part of the cycle and then returns back to it during other part of the cycle
(d) none of the above
Ans: c
Read More Questions:
A.C. Fundamentals MCQs Part1
A.C. Fundamentals MCQs Part2
(a) both waves must have same frequency
(b) both waves must have identical peak values
(c) both waves must have zero value at the same time
(d) none of the above
Ans: a
22. 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
Ans: c
23. Capacitive reactance is more when
(a) capacitance is less and frequency of supply is less
(b) capacitance is less and frequency of supply is more
(c) capacitance is more and frequency of supply is less
(d) capacitance is more and frequency of supply is more
Ans: a
24. In a series resonant circuit, the impedance of the circuit is
(a) minimum
(b) maximum
(c) zero
(d) none of the above
Ans: a
25. Power factor of an electrical circuit is equal to
(a) R/Z
(b) cosine of phase angle difference between current and voltage
(c) kW/kVA
(d) ratio of useful current to total current Iw/I
(e) all above
Ans: e
26. 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
Ans: b
27. Poor power factor
(a) reduces load handling capability of electrical system
(b) results in more power losses in the electrical system
(c) overloads alternators, transformers and distribution lines
(d) results in more voltage drop in the line
(e) results in all above
Ans: e
28. Capacitors for power factor correction are rated in
(a) kW
(b) kVA
(c) kV
(d) kVAR
Ans: d
29. In series resonant circuit, increasing inductance to its twice value and reducing capacitance to its half value
(a) will change the maximum value of current at resonance
(6) will change the resonance frequency
(c) will change the impedance at resonance frequency
(d) will increase the selectivity of the circuit
Ans: d
30. Pure inductive circuit
(a) consumes some power on average
(b) does not take power at all from a line
(c) takes power from the line during some part of the cycle and then returns back to it during other part of the cycle
(d) none of the above
Ans: c
Read More Questions:
A.C. Fundamentals MCQs Part1
A.C. Fundamentals MCQs Part2
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