The plates of a charged condenser is connected to a voltmeter. If the plates are moved apart, the reading of voltmeter will
a)	Increase	b)	Decrease
c)	Remain unchanged	d)	Information is insufficient

(a)

The capacitance (C) of a capacity is defined as the ratio of the charge (q) given to the rise in the potential (V) of the conductor. When the plates are moved apart, the charge remains constant, hence

Capacitance (C) of a parallel plate capacitor is given by

Where A is area of plates and d the separation between them.

From Eqs. (i) and (ii), we have

When plates are moved apart,  increases, hence value of C decreases and in order that charge (q) remains constant V increases.