The radius of the first Bohr orbit of hydrogen is `0.529A^(@)`. The radius of the `3^(rd)` orbit of `He^(+)` will be

Options

A. a)`8.46Å`
B. b)`0.705Å`
C. c)`1.59Å`
D. d) 4.29Å`

Answer

D

Explanation

According to Bohr model,
radius of hydrogen atom
`(r_(n))=(0.529xxn^(2))/(Z)Å`
where n = number of orbit
Z = atomic number
`r_(3)=(0.529xx(3)^(2))/(1)`
`=4.761Å`