In a Van de Graaff type generator a spherical metal shell is to be a `15xx10^6`v electode. The dielectic strangth of the gas surrounding the electrode is `5x10^7Vm^(-1)`. What is the minimum radius of the spherical shell required?

A spherical conductor of radius 12 cm has a charge 1.6xx10^(-7) C distributed uniformly on its surface. What is the electric filed inside the sphere

A fighter plane flying horizontally at an altitude of .1.5 km with speed 720 km/h passes directly overhead an anti-aircraft gun. At what angle from the vertical should the gun be fired for the shell with muzzle speed 600 m s^-1 to hit the plane? At what minimum altitude should the pilot fly the plane to avoid being hit? (Take g = 10 m s^-2) .

A spherical conductor of radius 12 cm has a charge 1.6xx10^(-7) C distributed uniformly on its surface. What is the electric filed outside the sphere.

A rocket is fired from the earth towards the sun. At what distance form the earth's centre is the gravitational force on the rocket zero? Mass of the sun = 2 xx 10^20 kg and mass of earth = 6 xx 10^24 kg and orbital radius 1.5 xx 10^-8 km.