### Electric Charges and Fields

goals

The electric field is $100 V/m$, at a distance of $20\ cm$ from the center of a dielectric sphere of radius $10\ cm$. Then E  at $3\ cm$ distance from the center of the sphere is :

A sphere carrying a charge of $0.01\ C$ is kept at rest without falling down, touching a wall by applying an electric field $100 \ N/C$. If the coefficient of friction between the sphere and the wall is $0.2$, the weight of the sphere is:

Three charges of respective values $- \sqrt{2} \mu C, 2\sqrt{2} \mu C$ and $-\sqrt{2} \mu C$ are arranged along a straight line as shown in the figure. Calculate the total electric field intensity due to all three charges at the point P.
A positive point charge Q is kept (as shown in the fig.) inside a neutral conducting shell whose centre is at C. An external uniform electric field E is applied. Then