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
A 1.0 μF capacitor is charged to 50v. The charging battery is disconnected and a 10mH coil is connectd across the condenser, so that L-C oscillations occur. The maximum current in the circuit (R = 0) is
9.25 A
0.5 A
0.75 A
1.0 A
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
The time constant of C - R circuit is
1/CR
C/R
CR
R/C
The effective value of an alternating current is 5A. The current passes through 24 Ω resistor. The maximum potential difference across the resistor is
10 V
170 V
17 V
1700 V
A coil of inductive reactance 31 Ω has a resistance of 8 Ω. It is placed in series with the condenser of capacitative reactance 25 Ω. The combination is connected to an AC source of 110 V. The power factor of the circuit is
0.56
0.64
0.80
0.33
Energy needed to establish an alternating current I in a coil of self inductance L is
L di/dt
zero
LI2/2
IL2/2
In an LCR series circuit, the capacitance is made one-fourth when in resonance. Then what should be the change in inductance so that the circuit remains in resonance?
4 times
¼ times
8 times
2 times
An alternating voltage V = 200√2 sin (100t) is connected to a 1μF capacitor through an AC ammeter. The reading of the ammeter shall be
10 mA
20 mA
40 mA
80 mA
In an AC circuit, Voltage and current are given by
V = 100 sin (100 t)
and I = 100 sin (100 t + π/3).
Calculate the power dissipation in the circuit ?
104 W
2.5 W
5 kW
10 W
