A capacitor of capacitance C is charged fully by connecting
it to a battery of Emf E. It is then disconnected from the
battery. If the separation between the plates of the capacitor
is now doubled what will happen to
(0) charge stored by the capacitor
() potential difference across it.
(111) field strength between the plates
(iv) energy stored by the capacitor.
(V) capacitance of the capacitor.
Answers
If the separation between the plates of the capacitor is doubled
1: As law of charge conservation states: The total electric charge in an isolated system never changes.
Hence charge stored by capacitor will not change.
2: Potential difference across capacitor is inversely proportional to capacitance as
V=Q/C
With distance between the plates of capacitor being doubled the capacitance gets halved as a result of which the potential difference gets doubled.
Hence the potential difference across capacitor gets doubled.
3: The field strength does not depend on distance between the plates of capacitor as E=Q^2/A£.
Hence field strength doesn't change with change in distance between the plates of capacitor.
4: The energy stored by capacitor is inversely proportional to capacitance as energy=Q^2/2C
As distance between the plates of capacitor is doubled the capacitance becomes half as a result of which the energy gets doubled.
Hence the energy stored by capacitor gets doubled if distance between the plates of capacitor is doubled.
5: Capacitance of capacitor is inversely proportional to distance between the plates of capacitor as
C=£A/d
Therefore if d is doubled capacitance becomes half of initial value.
Hence capacitance of capacitor becomes half of initial value.