Question

An electron is accelerated from rest through a potential difference of $12.27\text{V}$. The de Broglie wavelength of the electron is

• A. $19.1\mathring{\text{A}}$
• B. $12\mathring{\text{A}}$
• C. $4.81\mathring{\text{A}}$
• D. $3.5\mathring{\text{A}}$

Answer 1

The correct option is D $3.5\mathring{\text{A}}$

For an electron accelerated by potential difference $V$, de-Broglie wavelength is given by

$\lambda =\frac{h}{\sqrt{2m_{e}eV}}$

For electron, putting the values, we get

$\lambda =\frac{12.27}{\sqrt{V}}\mathring{\text{A}}=\frac{12.27}{\sqrt{12.27}}\approx 3.5\mathring{\text{A}}$