question_answer

The velocity of an electron in the inner most orbit of an atom will be:

A) highest                                

B) lowest

C)  mean                                  

D) zero

Correct Answer: A

Solution :

Let v be the velocity of electron, m the mass, r the radius and h the Planck's constant. Then velocity of electron in permitted orbit n is \[v=\frac{Z{{e}^{2}}}{2\,h{{\varepsilon }_{0}}}\frac{1}{n}\]               Where, Z is atomic number \[\Rightarrow \]     \[v\propto \frac{1}{n}\] This shows that the velocity of electron is maximum in the lowest orbit and goes on decreasing in higher orbits.