Figure shows a solid metal sphere of radius a surrounded by a concentric thin metal shell of radius 2a. Initially both are having charges Q each, When the two are connected by a conducting wire as shown in the figure, then amount of heat produced in this process will be :

Options

A. `(KQ^(2))/(2a)`
B. `(KQ^(2))/(4a)`
C. `(KQ^(2))/(6a)`
D. `(KQ^(2))/(8a)`

Answer

B

Explanation

`E_(1)=(KQ^(2))/(2a)+(KQ^(2))/(4a)+(KQ)/(2a).Q`
`=(KQ^(2))/(a)+(KQ^(2))/(4a)=(5Q^(2))/(4a)`
`E_(1)=(K(2Q)^(2))/(4a)=(KQ^(2))/(a)`
`E_(i)-E_(f)=H=(KQ^(2))/(4a)`