VITEEE 2012 Paper

Capacitance 1 µF and C µF are connectedin series,
∴ Ceq =

C

1+C

Given, V = 120 V and q = 8 µC
Since q = Ceq V
80 =

C

C+1

× 20
or C = 2 µF
Energy stored in the capacitor of capicity C
U =

1

2

q2

C

=

1

2

×

(80×10−6)2

2×10−6

=

1

2

×

80×10−6×80×10−6

2×10−6

U = 1600 µJ