a thin metallic spherical shell contains a charge Q on it. a point charge q is placed at de centre of de shell and another charge q is placed outside it. all de 3 charges r +ve.wat is de force on de charge at de centre?wat is de force on de central charge due to de shell ?

Sir,how q exert force on q 2wards left as electric field lines from q do not enter de shell? also why de shell exert force on charge q as electric field inside shell is zero ?

i m totally confused.

net force on the central charge is zero. actually due the external charge, charge distribution on the sphere is adjusted in such a way that the net resultant at the centre becomes zero. So the force on the central charge due to the spherical charge is equal and opposite to that of external charge.

both the spherical charge and external charge have individual effects soin absence sphere external charge exerts aforce on centrlcharge. the absence of electric field lines onlyy justify the NET EFFECT. so relating them with the individual effects of external charge and that of sphere will be WRONG.