The electric field in a certain region is acting radially outwards and is given by `E=Ar. A` charge contained in a sphere of radius `'a'` centred at the origin of the field, will given by

Options

A. `A epsilon_0 a^2`
B. `4 pi epsilon_0 Aa^3`
C. `epsilon_0 Aa^3`
D. `4 pi epsilon_0 Aa^2`

Answer

B

Explanation

E = Ar, R = a
Flux `phi=(q_("in"))/(epsilon_0)implies ES=(q_("in"))/(epsilon_0)`
`impliesq_("in")=epsilon_0(Aa) (4pi a^2)implies q_("in") = 4epsilon_0pi a^3A`