Consider a uniform spherical charge distribution of radius  R1 centred at the origin O.  In this distribution, a spherical cavity of radius  R2, centred at  P with distance  OP=a=R1−R2 (see figure) is made.  If the electric field inside the cavity at position  r→ is  E→r→, then the correct statement(s) is (are)

The sphere with cavity can be assumed as a complete sphere with +ve charge, radius  R1 + another complete sphere with –ve charge, radius R2 .Inside a spherical charge distribution for an internal point E→=ρ3ε0r→                     E+→E due to total +ve charges                             E−→E  due to total −ve  charges  Electric filed at any point inside cavity is given by,E→ =E→ ++E→ − ⇒E→=ρ3ε0r1→+-ρ3ε0r2→=ρ3ε0r1→-r2→=ρ3ε0a→                      E→  is uniform and both its magnitude and direction depend on  a→