An electron is moving round the nucleus of a hydrogen atom in a circular orbit of radius `r`. The coulomb force `vec(F)` between the two is (where `k=(1)/(4piepsilon_(0)))`

Options

A. `K(e^(2))/(r^(2))hatr`
B. `-K(e^(2))/(r^(2))hatr`
C. `-K(e^(2))/(r^(3))hatr`
D. `K(e^(2))/(r^(3))vecr`

Answer

B

Explanation

Nucleus of hydrogenn atom contains one proton of charge (+e). The revolving electron arries a charge (-e)
According to Coulomb.s law
`F=(K(e)(-e))/(r^(2)) hatr=-(Ke^(2))/(r^(3))=vecr`