According to classical physics, the kinetic energy K of an electron revolve in orbit of radius r is ........

Options

A. `(1)/(8piin_(0)).(Ze^(2))/(r)`
B. `(1)/(4piin_(0)).(Ze^(2))/(r)`
C. `-(1)/(8piin_(0)).(Ze^(2))/(r)`
D. `-(1)/(4piin_(0)).(Ze^(2))/(r)`

Answer

A

Explanation

For circular motion of electron in atom,
Centripetal force = Coulombian force
`(mv^(2))/(r)=(1)/(4piin_(0)).((Ze)(e))/(r^(2))`
`:.(1)/(2)mv^(2)=(1)/(8piin_(0)).(Ze^(2))/(r)`
`:.K=(1)/(8piin_(0)).(Ze^(2))/(r)`