Question

If 1 uF capacitor is fully charged with 120 V across it, how much energy is stored in it? (a) 7.2 kJ (b) 7.2 mJ (c) 0.12 mJ (d) 0.12 kJ

Answer 1

Answer:

(b) 7.2 mJ

Explanation:

ENERGY STORED IN CAPACITOR: the energy is stored in capacitor in electric field

which can be calculated by expressions

E=$\frac{1}{2}$ c $v{^2}$

=$\frac{1}{2}$ $10^{-6}$$120^{2}$

=7200×$10^{-6}$ J

= 7.2×$10^{-3}$ J

=7.2 mJ