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 meaning in cgs system)

Options

A. `2e^(2)//in_(0) hn^(2) c`
B. `2e^(2)//in_(0) hc`
C. `e^(2)//in_(0) hc`
D. `e^(2)//2 in_(0) hc`

Answer

D

Explanation

`v_(n)=e^(2)/(2 in_(0) nh)`
`v_(1)/c=e^(2)/(2 in_(0) hc)`