Question

Two parallel plate capacitors of capacitance C and 3C are connected in parallel and charged to a potential difference V with the help of a battery. The battery is disconnected and the space between these two capacitors are filled with dielectric of constant K and K/2 respectively. The voltage across the combination will be-

• A.
• B. $\frac { 6 \mathrm {~V} } { 3 \mathrm {~K} }$
• C. $\frac { 8 \mathrm {~V} } { 5 \mathrm {~K} }$
• D. $\frac { 3 \mathrm {~V} } { 5 \mathrm {~K} }$

Answer 1

Answer: (C)

$\frac { 8 \mathrm {~V} } { 5 \mathrm {~K} }$

Answer 2

Common potential = $\frac { \mathrm { q } _ { 1 } + \mathrm { q } _ { 2 } } { \mathrm { C } _ { 1 } + \mathrm { C } _ { 2 } }$ = $\frac { \mathrm { CV } + 3 \mathrm { CV } } { \mathrm { KC } + \frac { \mathrm { K } } { 2 } 3 \mathrm { C } }$

= =