Question

What is the de Broglie wavelength of the electron accelerated through a potential difference of $100$ Volt ?

• A. $12.27 \mathring{A}$
• B. $1.227 \mathring{A}$
• C. $0.1227 \mathring{A}$
• D. $0.001227 \, \mathring{A}$

Answer 1

Answer: (B)

de-Broglie wavelength of an electron is given by
$\lambda =\frac{h}{m v}=\frac{h}{\sqrt{2 m e V}}=\frac{12.27}{\sqrt{V}}\mathring{A}$
(h=Planck's constant)
where $m=$ mass of electron
$e=$ electronic charge and
$V=$ potential difference with which electron is accelerated
$\lambda =\frac{12.27}{\sqrt{100}} \mathring{A}=\frac{12.27}{10} \mathring{A}$
$=1.227\, \mathring{A}$