In the Bohr's orbit, what is the ratio of total kinetic energy and total energy of the electron

Options

A. `-1`
B. `-2`
C. 1
D. `+2`

Answer

A

Explanation

`KE =(1)/(2) mv^(2)`
`PE = -(Ze^(2))/(r )`
Electrostatic force = Centrifugal force
`:. (Ze^(2))/(r^(2)) =(mv^(2))/(r )`
`:. P.E. = -m v^(2)`
Total energy `= K.E. +P.E. = (1)/(2) mv^(2) - mv^(2)`
`= -(1)/(2) mv^(2)`
`:.` KE/Total energy `= -1`.