A 10 μ C capacitor and a 20 μ F capacitor are connected in series across a 200 V supply line. The charged capacitors are then disconnected from the line and reconnected with their positive plates together and negative plates together and no external voltage is applied. What is the potential difference across each capacitor?

Question

A 10 μ C capacitor and a 20 μ F capacitor are connected in series across a 200 V supply line. The charged capacitors are then disconnected from the line and reconnected with their positive plates together and negative plates together and no external voltage is applied. What is the potential difference across each capacitor? (A) (400/9) V (B) (800/9) V (C) 400 V (D) 200 V

Tardigrade Admin · Accepted Answer

Initially potential difference across each capacitor, V1=(20/(10+20)) × 200 =(400/3) V and V2=(10/(10+20)) × 200 =(200/3) V Finally common potential, V=(C1 V1+C2 V2/C1+C2) V=(10 × (400/3)+20 × (200/3)/(10+20)) =(800/9) V

$\frac{400}{9} V$

$\frac{800}{9} V$

400 V

200 V

9400​V

9800​V

400 V

200 V

Initially potential difference across each capacitor, V1​=(10+20)20​×200 =3400​V and V2​=(10+20)10​×200 =3200​V Finally common potential, V=C1​+C2​C1​V1​+C2​V2​​ V=(10+20)10×3400​+20×3200​​ =9800​V

$\frac{400}{9} V$

$\frac{800}{9} V$