Question

A capacitor of 16 micro-farads is connected to a 19 volt battery. The distance between the plates of the capacitor is reduced by a factor of 4.3 while the capacitor is still connected to the battery. What is the voltage across the capacitor after the distance between the plates is changed, in volts?

Answer 1

C = capacitance = 16 uF

V = Voltage across the capacitor = 19 Volts

Capacitance is given as

C = A/d                             where A = area of each plate , d = distance between the plates

as "d" is reducedby 4.3 factor , the capacitance increase by same factor and becomes 4.3 times

C' = new Capacitance = 4.3 C

Although the capacitance has increased , the value of Voltage across the plates will not change since Potential difference does not depend on the capacitance.

So Voltage = 19 Volts