A metal disc is winging freely between the poles of an electromagnet, as shown in the figure. When the electromagnet is switched on, the disc comes to rest after a few oscillations. Use Faraday's law of electromagnetic induction to explain why an e.m.f. is induced in the disc.

A metal disc is winging freely between the poles of an electromagnet, as shown in the figure. When the electromagnet is switched on, the disc comes to rest after a few oscillations. Explain why eddy currents are induced in the metal disc.

State Faraday's laws of electromagnetic induction and explain three methods for producing induced e.m.f.

A small retangular coil ABCD contains 140 turns of wire. The sides AB and BC of the coil are of length 4.5 and 2.8 cm respectively, as shown in the figure The coil is held between the poles of a large magnet so that the coil can rotate about an axis thorugh its centre. The magnet produces a uniform magnetic field of flux density B between its poles. When the current in the coil is 170 mA, the maximum torque produced in the coil is 2.1 xx 10^-3 N m . The current in the coil in (a) is switched off and the coil s positioned as shown in the figure. The coil is then turned thorugh an angle of 90^@ in a time of 0.14 s. Calculate the average e.m.f. induced in the coil.

Figure 6.20 shows a metal rod PQ resting on the smooth rails AB and positioned between the poles of a permanent magnet. The rails, the rod, and the magnetic field are in three mutual perpendicular directions. A galvanometer G connects the rails through a switch K. Length of the rod =15 cm, B = 0.50 T, resistance of the closed loop containing the rod = 9.0 mOmega Assume the field to be uniform. Suppose K is open and the rod is moved with a speed of 12 cm s^-1 in the direction shown. Give the polarity and magnitude of the induced emf. :

What is electromagnetic induction ? State its Faraday's laws. Find an expression for the e.m.f. induced due to change in the area of a coil lying in a uniform magnetic field.

A metal disc of radius 200 cm is rotated at a constant angular speed of 60 rad s^-1 in a plane at right angles to an external field of magnetic induction 0.05 Wb m^-1 . Find the e.m.f. induced between the centre and a point on the rim.

State laws of electromagnetic induction. A rectangular loop of N turns of length 'a' and width 'b' is rotated with an angular velocity omega in a uniform magnetic field of induction B. Show that induced e.m.f. is given by e = omega N b a B sin omegat

What is electromagnetic induction ? State its laws. Describe the methods for producing induced e.m.f. State the law by which the direction of induced current can be determined.