The adjacent diagram shows a charge `+Q` held on an insulating support `S` and enclosed by a hollow spherical conductor,`O` represent the center of the spherical conductors and `P` is a point such that `OP=x` and `SP=r` .The electric field at point `P` will be

Options

A. `Q/(4pi epsilon_0 x^2)`
B. `Q/(4pi epsilon_0 r^2)`
C. 0
D. None of the above

Answer

A

Explanation

According to gauss’s law
`ointvecE.dvecs=(Q_("in""))/(epsilon_0)`
`impliesE xx 4pix^2 =Q/(epsilon_0)`
`implies E=Q/(4pi epsilon_0x^2)`
Take a Gaussian surface radius R = x.