At a point 20 cm from the centre of a uniformly charged dielectric sphere of radius 10 cm, the electric field is 100 V /m. The electric field at 3 cm from the centre of the sphere will be

Electric field outside of the sphere, Eout=kQr2   .   .   .   iElectric field inside the dielectric sphere, Ein=kQxR3   .   .   .   iiFrom (1) and (11), Ein=Eout×r2xR⇒At  3 cm,  E=100×3202103=120V/m