Two coils have a mutual inductance of 0.005 H. The current changes in the first coil according to the equation I = I0 sin ωt where I0 = 10A and ω = 100π rad/sec. The maximum value of e.m.f. in the second coil is
5π volts
2π volts
π volts
4π volts
An aircraft has a wing span of 35 m. It is flying horizontally with a speed of 9.ms-1 and the vertical component of earth's magnetic field is 4 x 10-5T. The potential difference between the tips of the wings will be
12.6 V
0.126 V
1.26 V
0.013 V
In an experiment, 200 V AC is applied at the ends of an LCR circuit. The circuit consists of an inductive reactance (XL) = 50 Ω, capacitive reactance (XC) = 50 Ω and ohmic resistance (R) = 10 Ω. The impedance of the circuit is
10 Ω
20 Ω
30 Ω
40 Ω
In an AC circuit, the rms value of current, irms is related to the peak current, i0 by the relation
irms = √2i0
irms = πi0
irms = i0/π
irms = 1/√2 i0
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
A wire of resistance R is connected in series with an inductor of reactance ωL. Then quality factor of RL circuit is
Energy needed to establish an alternating current I in a coil of self inductance L is
L di/dt
Zero
LI2/2
IL2/2
A transformer is used to light a 100 W and 110 V lamp from a 220 V mains. If the main current is 0.5 A, the efficiency of the transformer is approximately
30%
50%
90%
10%
The time constant of C - R circuit is
1/CR
C/R
CR
R/C
A coil of resistance R and inductance L is connected to a battery of e.m.f. E volts. The final current in the coil is
