Question

$n$ identical condensers are joined in parallel and are charged to potential. Now they are separated and joined in series. Then the total energy and potential difference of the combination will be

• A. Energy and potential difference remain same
• B. Energy remains same and potential difference is $n V$
• C. Energy increases $n$ times and potential difference is $n V$
• D. Energy increases $n$ times and potential difference remains same

Answer 1

Answer: (B)

Energy remains same and potential difference is $n V$

Answer 2

According to energy conservation, energy remains the same

⇒ ⇒ $\frac { 1 } { 2 } ( n C ) V ^ { 2 } = \frac { 1 } { 2 } \left( \frac { C } { n } \right) V ^ { \prime 2 }$ ⇒ V' = nV

($V ^ { \prime }$= potential difference across series combination)