The radius of the second Bohr orbit for hydrogen atom is [Planck's constant `(h)=6.6262xx10^(-34)*s`, mass of electron=`9.1091xx10^(-31)kg`, charge of electron `=1.60210xx10^(-19)C`, permittivity of vacuum `(in_(0))=8.854185xx10^(-12)kg^(-1)*m^(-3)*A^(2)`]-

Options

A. 0.529 Å
B. 2.12 Å
C. 1.65Å
D. 4.76Å

Answer

B

Explanation

For hydrogen atom, the radius of n th Bohr orbit is,
`r_(n)=(n^(2)a_(0))/(Z)`Å
`therefore r_(2)=(2^(2)xx0.529)/(1)` Å `[becauseZ=1 and n=2]`
`=2.12`Å