Find out the energy content in a volume of `1 cm^3` around a point, situated in the electric field of a point charge of 10C, at a distance of 2 m in air from the position of the point charge. Given, `in_0 = 8.85 xx10^(-12)F*m^(-1)`.

Explanation

The electric field at the referred point due to the point charge,
`E= (1)/(4 pi in_0r^2) " "[" Here ", q =10C, r= 2m]`
Energy density at the point,
`u = (1)/(2)in_0 E^2= (1)/(2)in_0*(1)/(16pi^2 in_0^2) (q^2)/(r^4) = (q^2)/(32pi^2 in_0 r^4)`
The energy content in a volume of `1 cm^3,i.e., 10^(-6)m^3 , U =uxx10^(-6)`
`= (q^2)/(32pi^2 in_0 r^4)xx10^(-6)`
`= (10^2xx10^(-6))/(32 xx(3.14)^2 xx(8.85xx10^(-12)xx2^4)) approx 2240J`.