Question

An electron has kinetic energy $2.8\times {10}^{{}^{-23}}J$. de-Broglie wavelength nearly :
$(m_e=9.1\times {10}^{-31}kg)$

• A. $9.28\times {10}^{-4}m$
• B. $9.28\times {10}^{-7}m$
• C. $9.28\times {10}^{-8}m$
• D. $9.28\times {10}^{-10}m$

Answer 1

Answer: (C)

$9.28\times {10}^{-8}m$

The formula for de Broglie wavelength is

$\lambda =\frac{h}{\sqrt{2mE}}$

where

λ is wavelength,

h is Planck's constant,

m is the mass of a particle

E is the kinetic energy of an electron

$\lambda =\frac{6.626\times {10}^{-34}}{\sqrt{2\times 9.1\times {10}^{-31}\times 2.8}\times {10}^{-23}}$

$\lambda =9.28\times {10}^{-8}m$

Hence, the correct option is $C$