The phase difference between voltage and current wave through a circuit element is given as 30°. The essential condition is that Both waves must have same frequency Both waves must have zero value at the same time None of the listed here Both waves must have identical peak values TRUE ANSWER : ? YOUR ANSWER : ?
The period of a sine wave is ___________ seconds. Its frequency is 30 Hz 20 Hz 40 Hz 50 Hz TRUE ANSWER : ? YOUR ANSWER : ?
The series and parallel resonance on L-C circuit' differs in that Series resistance needs a low-resistance source for sharp rise in current Parallel resonance needs a low-resistance source for a sharp rise in line current Series resonance needs a high-resistance source for sharp increase in current Parallel resonance needs a low-resistance source for a sharp increase in impedance TRUE ANSWER : ? YOUR ANSWER : ?
Time constant of a circuit is the time in seconds taken after the application of voltage to each 63% of maximum value 25% of maximum value 50% of maximum value 90% of the maximum value TRUE ANSWER : ? YOUR ANSWER : ?
In a pure inductive circuit if the supply frequency is reduced to 1/2, the current will Be reduced by half Be reduced to one fourth Be doubled Be four times as high TRUE ANSWER : ? YOUR ANSWER : ?
The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of Skin effect Iron loss in core Capacitive effect between adjacent coil turns Increase in temperature TRUE ANSWER : ? YOUR ANSWER : ?
Power factor of the system is kept high To maximize the utilization of the capacities of generators, lines and transformers All of the listed here To reduce voltage regulation of the line To reduce line losses TRUE ANSWER : ? YOUR ANSWER : ?
The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is 12 kVAR 10 kVAR 16 kVAR 8 kVAR TRUE ANSWER : ? YOUR ANSWER : ?
Which of the following waves has the highest value of peak factor ? Triangular wave Sine wave Half wave rectified sine wave Square wave TRUE ANSWER : ? YOUR ANSWER : ?
An A.C. voltage is impressed across a pure resistance of 3.5 ohms in parallel with a pure inductance of impedance of 3.5 ohms, The current through the resistance is more None of the listed here Both resistance and inductance carry equal currents The current through the resistance is less TRUE ANSWER : ? YOUR ANSWER : ?