Q. The speed of an electron having a wavelength of $10^{- 10}m$ is
A) $7.25 \times 10^{6}m/s$
B) $6.26 \times 10^{6}m/s$
C) $5.25 \times 10^{6}m/s$
D) $4.24 \times 10^{6}m/s$
Explanation
(a) By using $\lambda_{electron} = \frac{h}{m_{e}v} \Rightarrow v = \frac{h}{m_{e}\lambda_{e}}$
$= \frac{6.6 \times 10^{- 34}}{9.1 \times 10^{- 31} \times 10^{- 10}} = 7.25 \times 10^{6}m/s$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.