Define surface charge density .

Define surface energy.

A spherical conducting shell of inner radius r_(1) and outer radius r_(2) has a charge Q. (a) A charge q is placed at the centre of the shell. What is the surface charge density on the inner and outer surfaces of the shell? (b) Is the electric field inside a cavity (with no charge) zero, even if the shell is not spherical, but has any irregular shape? Explain.

The earth's surface has-a negative surface charge density of 10^(-9) Cm^(-2) . The potential difference of 400kV between the top of the atmosphere and the surface results in a current of only 1800A over the entire globe. If there were no mechanism of sustaining atmospheric electric field, how much time would be required to neutralize the earth's surface charge? Take radius of earth = 6.37xx 10^(6) m.

A uniformly charged conducting sphere of 2.4 m diameter has a surface charge density of 80xx10^(-6)cm^(-2) a. Find the charge on the sphere. b. What is the total electric flux leaving the surface of the sphere?

Use Gauss s law to derive the expression for the electric field between two uniformly charged large parallel sheets with surface charge densities sigma and -sigma respectively .