Class XII Physics Electromagnetic Induction 3

A metal disc rotates freely, between the poles of a magnet in the direction indicated. Brushes P and Q make contact with the edge of the disc and the metal axle. What current, if any, flows through R?

Two coils are at fixed locations. When coil 1 has no current and the current in coil 2 increases at the rate 15.0 A/s the e.m.f. in coil 1 in 25.0 mV, when coil 2 has no current and coil 1 has a current of 3.6 A, flux linkage in coil 2 is-

A long straight wire is placed along the axis of a circular ring of radius R. The mutual inductance of this system is-

A closed circuit consists of a source of emf E and an inductor coil of inductance L connected in series. The active resistance of whole circuit is R. At the moment t = 0 the inductance of coil abruptly decreased to . Then current in the circuit immediately after is -

Consider the situation shown in figure. If the current I in the long straight wire XY is increased at a steady rate then the induced emf's in loops A and B will be-

A square wire loop of 10.0 cm side lies at right angles to a uniform magnetic field of 20T. A 10 V light bulb is in a series with the loop as shown in the figure. The magnetic field is decreasing steadily to zero over a time interval Δt. The bulb will shine with full brightness if Δt is equal to -

Shown in the figure is a circular loop of radius r and resistance R. A variable magnetic field of induction B = B₀e^–t is established inside the coil. If the key (K) is closed, the electrical power developed right after closing the switch is equal to

A ring having mass ‘m’ radius ‘r’ is rolling on a rough horizontal plane. An uniform horizontal magnetic field B = B₀ is exists in space as shown in figure. Along which two points induced e.m.f. is maximum (here V is linear speed & w is angular speed)