Question

How many times does light travel faster in vacuum than an electron in Bohr first orbit of hydrogen atom?

• A. $13.7$ times
• B. $67$ times
• C. $137$ times
• D. $97$ times

Answer 1

Answer: (C)

$137$ times

Velocity of electron in $n^{th}$ orbit = $V_0\frac{z}{n}$ , according to Bohr model.

where $V_0=2.18\times {10}^{6}m/s$

For hydrogen's first orbit , $z=1,n=1$

Speed of light =$3\times {10}^{8}m/s$

Let $3\times {10}^8=x(2.16\times {10}^6)$

$⟹x=137$

Speed of light is 137 times faster.