but how does it happen so..

effectively how does it become lik 1st figure.. 

as far as my understanding, with ur xplanation i understand that on polarization, separation of charge takes place and + ve and -ve charge comes on both the surfaces. that means 2nd figure notation is correct but if so then there will be 2 induced field and they will itself going to cancel each other.

i am still not getting.

As shown in the figure, there are non-conducting hollow sphere and a positive charge q outside.    why does the induction takes place as shown in 1st figure. why not it takes place like 2nd figure? 

A hollow uncharged conducting sphere of radius R and a charge +q is kept at distance r from the centre of the sphere and rR . the electric field at the centre of the sphere due to induced charge on it, is