Two capacitors of capacities `1 mu`F and C `mu`F are connected in series and the combination is charged to a potential difference of 120 V. If the charge on the combination is 80 `mu`C, the energy stored in the capacitor of capacity C in `mu`J is

Options

A. 1800
B. 1600
C. 14400
D. 7200

Answer

(b)

Explanation

Equivalent capacitance of capacitors connected in series ,
`C_(eq) = C/1+C`
Charge in combination is , `q =C_(eq)V`
`C/(1 + C) = 80/120`
`rArr 3C = 2 + 2C`
C= `2mu`F
The energy stored in the capacitor of capicity C is,
`U = 1/2 q^(2)/C = 1/2 (80 xx 10^(-6))_(2)/2 xx 10^(-6) = 1600 mu` J