The ratio of the speed of the electron in the first Bohr orbit of hydrogen and the speed of light is equal to (where `e, h` and `c` have their usual meanings)

Options

A. `(2pihc)/(e^(2))`
B. `(e^(2)c)/(2pih)`
C. ` (e^(2)h)/(2pihc)`
D. `(e^(2))/(2epsi_(0)hc)`

Answer

D

Explanation

Speed of electron in first orbit of hydrogen atom is given by
`" " v=(e^(2))/(2epsi_(0)h)`
` :. " " (v)/(c)=(e^(2))/(2epsi_(0)hc)`