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

(b) 7.2 mJ

Step-by-step explanation:

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

which can be calculated by expressions

E=
`(1)/(2)` c
`v{^2}`

=
`(1)/(2)`
`10^(-6)`
`120^(2)`

=7200×
`10^(-6)` J

= 7.2×
`10^(-3)` J

=7.2 mJ