A heater is rated as 230 V, 10 kW, A.C. The value 230 V refers to__________?
(A) average voltage
(B) r.m.s. voltage
(C) peak voltage
(D) none of the above
The voltage of domestic supply is 220V. This figure represents__________?
(A) mean value
(B) r.m.s. value
(C) peak value
(D) average value
If two sinusoids of the same frequency but of different amplitudes and phase angles are subtracted, the resultant is____________?
(A) a sinusoid of the same frequency
(B) a sinusoid of half the original frequency
(C) a sinusoid of double the frequency
(D) not a sinusoid
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
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
(B) will change the resonance frequency
(C) will change the impedance at resonance frequency
(D) will increase the selectivity of the circuit
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
(D) results in all above
Time constant of an inductive circuit___________?
(A) increases with increase of inductance and decrease of resistance
(B) increases with the increase of inductance and the increase of resistance
(C) increases with decrease of inductance and decrease of resistance
(D) increases with decrease of inductance and increase of resistance
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
For a frequency of 200 Hz, the time period will be__________?
(A) 0.05 s
(B) 0.005 s
(C) 0.0005 s
(D) 0.5 s