Question

If the speed of electrons in Bohr's first obtain of hydrogen is ${}^{\prime }{X}^{\prime }$ the speed of electrons in third orbit is:

• A. $\frac{X}{9}$
• B. $\frac{X}{3}$
• C. $3X$
• D. $9X$

Answer 1

The correct option is B $\frac{X}{3}$

We know,

$v=v_{0}z/n$ here $v_0=X=$ velocity of elctron in first orbit of hydrogen or velocity constant

for third orbit of hydrogen atom value of n is 3 and z is 1

So $v=\frac{X}{3}$