A rectangular wire frame, as shown in figure (a) is placed in uniform magnetic field directed upward and normal to the plane of the paper. The part AB is connected to a spring. The spring is stretched and released when the wire AB has come to the position A'B' (t=0).
Explain qualitatively how induced emf in the coil would vary with time. Neglect damping of oscillations of the spring.
The current flowing in the two coils of self-inductance L1 = 16 mH and L2 = 12 mH are increasing at the same rate. If the power supplied to the two coils are equal, then find the ratio of:
induced voltages
the currents
the energies stored in the two coils at a given instant.
State the Faraday's law of electromagnetic induction.
Define mutual inductance.
Write its SI unit.
Give two factors on which the coefficient of mutual inductance between a pair of coils depends.
Predict the polarity of the capacitor in the situation described by the adjoining figure. Explain the reason too.
Define mutual inductance. Give its SI unit.
A small flat search coil of area 5 cm2 with 140 closely wound turns is placed between the poles of a powerful magnet producing magnetic field 0ยท09 T and then quickly removed out of the field region. Calculate:
The motion of copper plates is damped when it is allowed to oscillate between the two poles of a magnet. If slots are cut in the plate, how will the damping be affected?
A coil Q is connected to low voltage bulb B and placed near another coil P as shown in Figure. Give reasons to explain the following observations:
The bulb 'B' lights.
Bulb gets dimmer if the coil Q is moved towards left.
A pair of adjacent coils has a mutual inductance of 1.5 H. If the current in one coil changes from 0 to 20 A in 0.5 s, what is the change of flux linkage with the other coil?