An alternating voltage E = 220√2 sin 100 t is connected to 1μF capacitor through an a.c. ammeter. The reading of the ammeter shall be
22 mA
10 mA
40 mA
80 mA
An a.c. circuit having an inductor and a resistor in series, draws a power of 560 W from an a.c. source marked 210 V, 60 Hz. If power factor of the circuit is 0.8, then impedance of the circuit is
103 Ω
63 Ω
12 Ω
114 Ω
A wire of resistance R is connected in series with an inductor of reactance ωL. Then quality factor of RL circuit is
A lamp consumes only 25% of peak power in an a.c. circuit. What is the phase difference between the applied voltage and the circuit current?
π/6
π/2
π/3
π/4
A 20 V a.c. is applied to a circuit consisting of resistance and a coil of negligible resistance. If the voltage across resistance is 12V,then voltage across the coil is
10 V
8 V
6 V
16 V
The primary and secondary coils of a transformer have 50 and 1500 turns respectively. If the magnetic flux Φ linked with the primary coil is given by Φ = Φ0 + 4t, where Φ is in weber, t is time in second and Φ0 is a constant, the output voltage across the secondary coil is
90 V
120 V
220 V
30 V
The time constant of C - R circuit is
1/CR
C/R
CR
R/C
A L-C circuit is in a state of resonance. If C = 0.1 μF and L = 0.25 H, then neglecting the ohmic resistance of the circuit, find the frequency of oscillations.
1007 Hz
100 Hz
109 Hz
500 Hz
In an a.c. circuit, the current is i = 5 sin (100t -π/2) amp and the a.c. voltage is v = 200 sin (100 t) volts. Then power consumption is
200 W
0 W
40 W
1000 W
An AC supply gives 30 Vrms which passes through a 10 Ω resistance. The power dissipated in it is
90 √2 W
90 W
45√2 W
45 W