A shellof radius Rhasa chargeQ unifromly distributed over it .A point chargeq isplaced at the centerof the shell . Find theworkdonetoincrease the radiusof theshell from R to 2R ?

A shellof radius Rhasa chargeQ unifromly distributed over it .A point

1.	A shellof radius Rhasa chargeQ unifromly distributed over it .A point chargeq isplaced at the centerof the shell . Find theworkdonetoincrease the radiusof theshell from R to 2R ?
Answer» Solution :`U_(i) = (U_(s) + U_(int)) ` initially `(Q^(2))/( 8 pi in_(0)R) + (1)/(4 pi in_(0)) (Qq)/(R)` `U_(f) = (U_(s) + U_("int"))`FINALLY ` = (Q^(2))/(16pi in_(0)R) + (1)/(8pi in_(0)) (Qq)/(R)` Work doneby theelectric FIELD` = U_(i) - U_(f)` ` = (Q)/(8 pi in_(0)R)((Q)/(2) + q)`