Question

Calculate the wavelength of an electron moving with a kinetic energy of $18.62\times {10}^{-25}J$.

Answer 1

As we know,
$KE=\frac{1}{2}m{v}^2$ and $m=9.31\times {10}^{-31}kg$

$=\frac{1}{2}\times 9.31\times {10}^{-31}\times v^2=18.62\times {10}^{-25}$

$v^2=\frac{18.62\times {10}^{-25}\times 2}{9.31\times {10}^{-31}}=4\times {10}^6$

$v=2\times {10}^{3}m{s}^{-1}$

Now, use the de Broglie's wavelength formula to find out the wavelength of the electron.

$\lambda =\frac{h}{mv}$