Electromagnetic Induction

Figure shows the circuit that contains three resistances (9 each) and two inductors (4 mH each). The reading of ammeter at the moment switch K is turned ON, is A. [figure]

1. 2
2. 3
3. 1
4. zero

A conducting circular loop is rotated about its diameter at a constant angular speed of 100 rad/s in a magnetic field of 0.5 T perpendicular to the axis of rotation. When the loop is rotated by 30 from the horizontal position, the induced EMF is 15.4 mV. The radius of the loop is mm. (Take = 227)

A conducting circular loop of area 1.0 m2 is placed perpendicular to a magnetic field which varies as B = (100t) Tesla. If the resistance of the loop is 100 , then the average thermal energy dissipated in the loop in one period is J.

1. 2
2. 2
4. 2

A 1 m long metal rod AB completes the circuit as shown in figure. The area of circuit is perpendicular to the magnetic field of 0.10 T. If the resistance of the total circuit is 2 then the force needed to move the rod towards right with constant speed (v) of 1.5 m/s is N. [figure]

1. 5.7 10-2
2. 7.5 10-3
3. 5.7 10-3
4. 7.5 10-2

Conductor wire ABCDE with each arm 10 cm in length is placed in magnetic field of 1 2 Tesla, perpendicular to its plane. When conductor is pulled towards right with constant velocity of 10 cm/s, induced emf between points A and E is mV. [figure]

A solenoid having area A and length 'l' is filled with a material having relative permeability 2. The magnetic energy stored in the solenoid is :

1. B2Al4 0
2. B2Al2 0
3. B2Al 0
4. B2Al

A coil of area A and N turns is rotating with angular velocity in a uniform magnetic field B about an axis perpendicular to B. Magnetic flux and induced emf across it, at an instant when B is parallel to the plane of coil, are :

1. = AB, = NAB
2. = AB, = 0
3. = 0, = 0
4. = 0, = NAB

Consider I1 and I2 are the currents flowing simultaneously in two nearby coils 1 & 2, respectively. If L1 = self inductance of coil 1, M12 = mutual inductance of coil 1 with respect to coil 2, then the value of induced emf in coil 1 will be :

1. e1 = -L1 dI2dt - M12 dI1dt
2. e1 = -L1 dI1dt + M12 dI2dt
3. e1 = -L1 dI1dt - M12 dI1dt
4. e1 = -L1 dI1dt - M12 dI2dt

A uniform magnetic field of 0.4 T acts perpendicular to a circular copper disc 20 cm in radius. The disc is having a uniform angular velocity of 10 rad s-1 about an axis through its centre and perpendicular to the disc. What is the potential difference developed between the axis of the disc and the rim? ( = 3.14)

1. 0.5024 V
2. 0.0628 V
3. 0.2512 V
4. 0.1256 V

[figure] A conducting bar moves on two conducting rails as shown in the figure. A constant magnetic field B exists into the page. The bar starts to move from the vertex at time t = 0 with a constant velocity. If the induced EMF is E tn, then value of n is .