Question

Calculate the wavelength associated with an electron moving with a velocity of ${10}^{9}cm/s.$

• A. $0.73\stackrel{\circ }{A}$
• B. $0.82\stackrel{\circ }{A}$
• C. $0.67\stackrel{\circ }{A}$
• D. $1.01\stackrel{\circ }{A}$

Answer 1

The correct option is A $0.73\stackrel{\circ }{A}$

Given,
$\text{Velocity of electron}\left(v\right)={10}^{9}cm/s$

We know that,
$\text{Planck's constant}\left(h\right)=6.63\times {10}^{-27}ergs$
$\text{Mass of electron}\left(m_e\right)=9.1\times {10}^{-28}g$

Again,
$\text{de Broglie wavelength}\left(\lambda \right)=\frac{h}{mv}$
$=\frac{6.63\times {10}^{-27}}{9.1\times {10}^{-28}\times {10}^9}$$=7.28\times {10}^{-9}cm$
$=0.73\stackrel{\circ }{A}$