CBSE
Multiple Choice QuestionsThe maximum value of AC voltage in a circuit is 707 V. Its rms value is
70.7 V
100 V
500 V
707 V
If an alternating voltage is represented as E = 141 sin (628 t), then the rms value of the voltage and the frequency are respectively
141 V, 628 Hz
100 V, 50 Hz
100 V, 100 Hz
141 V, 100 Hz
A step-down transformer is used on a 1000 V line to deliver 20 A at 120 V at the secondary coil. If the efficiency of the transformer is 80%, the current drawn from the line is
3 A
30 A
0.3 A
2.4 A
An alternating current of rms value 10 A is passed through a 12 Ω resistor. The maximum potential difference across the resistor is
20 V
90 V
169.68 V
None of these
In the circuit shown below, the switch is kept in position a for a long time and is then thrown to position b. The amplitude of the resulting oscillating current is given by
E / R
infinity
