Question

How many times does the electron go around the first Bohr's orbit of hydrogen in one second?

• A. $4.00\times {10}^{15}$
• B. $2.25\times {10}^{15}$
• C. $6.59\times {10}^{15}$
• D. $1.10\times {10}^{14}$

Answer 1

The correct option is C $6.59\times {10}^{15}$

Number of revolutions per second $=\frac{v}{2\pi r}$
$v=\frac{2.188\times {10}^8}{n}cm/sec=2.188\times {10}^{8}cm/sec$
$r=n^2\times 0.529\times {10}^{-8}cm=1^2\times 0.529\times {10}^{-8}cm=0.529\times {10}^{-8}cm$
$\therefore$ Number of revolutions per sec
$=\frac{2.188\times {10}^{8}cm}{2\times 3.14\times 0.529\times {10}^{-8}}=6.59\times {10}^{15}$