Obtain an expression for the current in a capacitor when an a.c.em.f. is applied.

Obtain an expression for effective capacitance of two capacitors in series.

Explain the term 'drift velocity' of electrons in a conductor. Hence obtain the expression for the current through a conductor in terms of 'drift velocity'.

Obtain an expression for equivalent capacitance when three capacitors C_1, C_2 and C_3 are connected in series.

The gap between the plates of a parallel plate capacitor is filled with glass of resistivity rho . The capacitance of the capacitor without glass equals C. The leakage current of the capacitor when a voltage V is applied to it is

(a) State the underlying principle of a potentiometer. Why is it necessary to (i) use a long wire, (ii) have uniform area of cross-section of the wire ? (b) Obtain an expression for equivalent capacitance when three capacitors C_(1), C_(2) "and" C_(3) are connected in series.

How does Ampere-Maxwell law explain the flow the of current through a capacitor when it is being charged by a battery? Write the expression for the displacement current in terms of the rate of change of electric flux.

Derive the expression for the current density of a conductor in terms of the conductivity and applied electic field. Explain with reason how the mobility of electrons in a conductor changes when the potential difference applied is doubled, keeping the temperature of the conductor constant.

A 200 Omega resistor is connected in series with a 5(mu)F capacitor. The voltage across the resistor is V_(R )=(1.20 V) cos (2500 rad s^(-1))t . (a) Derive an expression for the circuit current. (b) Determine the capacitive reactance of the capacitor.

(b) Obtain the expression for the capacitance of a parallel plate capacitor.

Obtain the expression for the magnetic energy stored in an ideal inductor of self inductance L when a current I passes through it. Hence obtain the expression for the energy density of magentic field produced in the inductor.