According to Boohr's theory the angular momentum of an electron in 5th orbit is :

Options

A. `25h//pi`
B. `2.5h/pi`
C. `1.0h//pi`
D. `10h//pi`

Answer

B

Explanation

According to Bohr's theory, the angular momentum of an electron is always an intergral multiple of `h//2pi`, i.e.,
`mvr = n (h)/(2pi)`
where `n` is the orbit number (principal quantum number). Thus, for the `5th` orbit, we have
`mvr = 5((h)/(2pi)) = 2.5 (h)/(pi)`