Question

The wavelength of an electron moving with velocity of ${10}^{7}m{s}^{-1}$ is:

• A. $7.27\times {10}^{-11}m$
• B. $3.55\times {10}^{-11}m$
• C. $8.25\times {10}^{-4}m$
• D. $1.05\times {10}^{-16}m$

Answer 1

Answer: (A)

$7.27\times {10}^{-11}m$

According to de Broglie's equation, $\lambda =\frac{h}{mv}$

Where, $\lambda =$ de-Broglie wavelength and $h=6.626\times {10}^{-34}Js$=Planck's constant

$m=$mass of electron$=9.1\times {10}^{-31}$ kg and $v=$ velocity$={10}^7$ m/s

upon substitution we get:

$\lambda =\frac{6.626\times {10}^{-34}\times 3600}{9.1\times {10}^{-31}\times {10}^7}$

$\lambda =0.727\times {10}^{-10}=7.27\times {10}^{-11}$m

Hence, the correct option is $A$