Question

The speed of an electron having a wavelength of the order of $1\stackrel{\circ }{A}$ will be

• A. $7.25\times {10}^6\text{m}/\text{s}$
• B. $6.26\times {10}^6\text{m}/\text{s}$
• C. $5.25\times {10}^6\text{m}/\text{s}$
• D. $4.24\times {10}^6\text{m}/\text{s}$

Answer 1

The correct option is A $7.25\times {10}^6\text{m}/\text{s}$

$v=\frac{p}{m}=\frac{h}{m\lambda }=\frac{6.6\times {10}^{-34}}{9.1\times {10}^{-31}\times {10}^{-10}}=7.25\times {10}^6\text{m}/\text{s}$