Question

The kinetic energy of electron is $3.0\times {10}^{-25}J$. The wavelength of the electron is:

• A. $7965\mathring{A}$
• B. $4625\mathring{A}$
• C. $91\mathring{A}$
• D. $8967\mathring{A}$

Answer 1

The correct option is D $8967\mathring{A}$

For electron

$\lambda =\frac{h}{mv}$ $p=\sqrt{2km}$

$\lambda =\frac{h}{\sqrt{2km}}$ , $\lambda =\frac{6.6\times {10}^{-34}}{\sqrt{2\times 3\times {10}^{-25}\times 9.1\times {10}^{-31}}}$

$\lambda =0.8967\times {10}^{-6}m=8967\mathring{A}$