Question

The de-Broglie wavelength of an electron of speed $0.5km{s}^{-1}$ is

• A. $1.5\times 10^{-6}m$
• B. $1.5\times 10^{-8}m$
• C. $1.5\times 10^{-10}m$
• D. $1.5\times 10^{-12}m$

Answer 1

Answer: (A)

$\lambda =\frac{h}{p}=\frac{h}{mv}$
$\Rightarrow \lambda =\frac{6.6\times 10^{-34}Js}{\left(9.1\times 10^{-31}kg\times 500m{s}^{-1}\right)}=1.5\times 10^{-6}m$