a)State Gauss’s law in electrostatics. Show that with help of suitable figure that outward flux due to a point charge Q, in vacuum within gaussian surface, is independent of its size and shape.
b) In the figure there are three infinite long thin sheets having surface charge density `+2sigma, -2sigma and +sigma` respectively. Give the magnitude and direction of electric field at a point to the left of sheet of charge density `+2sigma` and to the right of sheet of charge density `+sigma`