A small metallic sphere carrying charge `+Q` is located at the centre of a spherical cavity in a large uncharged metallic spherical shell . Write the charges on the inner and outer surfaces of the shell . Write the expression for the electric field at the point `P_(1)`.

Explanation

Charge on inner surface :- Q
Charge on outer surface : +Q
Electric field at point `P_(1)`
`E=(1)/(4piepsilon_(0))(Q)/(r_(1)^(2))`