As shown in the figure, a point charge \( Q \) is placed at the centre of conducting spherical shell of inner radius \( a \) and outer radius \( b \). The electric field due to charge \( Q \) in three different regions \( I \), \( II \) and \( III \) is given by: \( ( I : r < a , \, II : a < r < b , \, III : r > b ) \).
