A point charge causes an electric flux of `-1.0xx10^(3) N m^(2)//C` to pass through a spherical Gaussian surface of 10.0 cm radius centred on the charge. (a) If the radius of the Gaussian surface were doubled, how much flux would pass through the surface ? (b) What is the is the value of the point charge ?

Explanation

(a) On increasing the radius of the Gaussian surface, there will be no change in the enclosed charge because the point charge is kept at the centre. The electric flux will remain the same as `-10^3 N m^2 //C`
(b)Using Gauss.s law we have :
`phi=q_"in"/epsilon_0`
`rArr q_"in"=-10^(3) xx8.85xx10^(-12)`
`=-8.85xx10^(-9)` C
=-8.85 nC