# Shown in the figure are two point charges +Q and -Q inside the cavity of a spherical shell. The charges are kept near the surface of the cavity on opposite sides of the centre of the shell. If is the surface charge on the inner surface and Q1 net charge on it and the surface charge on the outer surface and Q2 net charge on it then : Option 1) Option 2) Option 3) Option 4)

As we learnt in

if Electric field is variable -

$\dpi{100} \phi = \int \vec{E}\cdot d\vec{A}$

-

Inside the cavity net charge is zero

$\therefore Q_1 = 0\: and \: \sigma_1 \neq 0$

There is no effect of point charge and induced charge on the inner surface and the outer surface

$\therefore Q_2 = 0\: and \: \sigma_2 = 0$

Option 1)

Incorrect

Option 2)

Incorrect

Option 3)

Correct

Option 4)

Incorrect

N

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