Electromagnetic Induction

In a coil, the current changes from -2 A to +2 A in 0.2 s and induces an emf of 0.1 V. The self inductance of the coil is :

1. 4 mH
2. 2.5 mH
3. 1 mH
4. 5 mH

Two conducting circular loops A and B are placed in the same plane with their centres coinciding as shown in figure. The mutual inductance between them is: [figure]

1. 02 b2a
2. 0 a22b
3. 0 b22a
4. 02 a2b

The current in an inductor is given by I = (3t + 8) where t is in second. The magnitude of induced emf produced in the inductor is 12 mV. The self-inductance of the inductor mH.

A rod of length 60 cm rotates with a uniform angular velocity 20 rad s-1 about its perpendicular bisector, in a uniform magnetic field 0.5 T. The direction of magnetic field is parallel to the axis of rotation. The potential difference between the two ends of the rod is V.

A rectangular loop of sides 12 cm and 5 cm, with its sides parallel to the x-axis and y-axis respectively, moves with a velocity of 5 cm/s in the positive x axis direction, in a space containing a variable magnetic field in the positive z direction. The field has a gradient of 10-3 T/cm along the negative x direction and it is decreasing with time at the rate of 10-3 T/s. If the resistance of the loop is 6 m , the power dissipated by the loop as heat is 10-9 W.

A coil of 200 turns and area 0.20 m2 is rotated at half a revolution per second and is placed in uniform magnetic field of 0.01 T perpendicular to axis of rotation of the coil. The maximum voltage generated in the coil is 2 volt. The value of is .

A coil is placed perpendicular to a magnetic field of 5000 T. When the field is changed to 3000 T in 2 s, an induced emf of 22 V is produced in the coil. If the diameter of the coil is 0.02 m, then the number of turns in the coil is:

1. 35
2. 70
3. 7
4. 140

A small square loop of wire of side l is placed inside a large square loop of wire of side L (L=l2 ). The loops are coplanar and their centers coincide. The value of the mutual inductance of the system is x 10-7 H, where x= .

The magnetic flux (in weber) linked with a closed circuit of resistance 8 varies with time (in seconds) as =5t2-36t+1. The induced current in the circuit at t=2 s is A.

A ceiling fan having 3 blades of length 80 cm each is rotating with an angular velocity of 1200 rpm. The magnetic field of earth in that region is 0.5 G and angle of dip is 30 . The emf induced across the blades is N 10-5 V. The value of N is .