Explain why the reactance offered by an inductor increases with increasing frequency of an alternating voltage.

Find the electric field intensity due to a uniformly charged spherical shell at a point (i) outside the shell and (ii) inside the shell. Plot the graph of electric field with distance from the centre of the shell.

Given below are two electric circuits A and B.

Calculate the ratio of power factor of the circuit B to the power factor of circuit A.

State the principle of a cyclotron. Show that the time period of revolution of particles in a cyclotron is independent of their speeds. Why is this property necessary for the operation of a cyclotron?

Both alternating current and direct current are measured in amperes. But how is the ampere defined for an alternating current?

1. Write three characteristic properties of nuclear force.
2. Draw a plot of potential energy of a pair of nucleons as a function of their separation. Write two important conclusions that can be drawn from the graph.

1. When an AC source is connected to an ideal inductor show that the average power supplied by the source over a complete cycle is zero.
2. A lamp is connected in series with an inductor and an AC source. What happens to the brightness if the lamp when the key is plugged in and an iron rod is inserted inside the inductor? Explain.

Draw a circuit diagram to study the input and output characteristics of an n-p-n transistor in common emitter configuration. Explain briefly how this arrangement is used to obtain the typical input/output characteristics of a transistor. Draw the graphs showing the nature of input/output curves.

Calculate the equivalent capacitance between points A and B in the circuit below. If a battery of 10 V is connected across A and B, calculate the charge drawn from the battery by the circuit.