Question

An electron microscope is used to probe the atomic arrangements to a resolution of 5$\AA$. What should be the electric potential to which the electrons need to be accelerated ?

• A. 2.5 V
• B. 5 V
• C. 2.5 kV
• D. 5 kV

Answer 1

Answer: (B)

5 V

Answer 2

$\lambda=\frac{h}{\sqrt{2 e V m}}$ $5 \,??,{A}=\frac{6.6 \times 10^{-34}}{\sqrt{2 \times 1.6 \times 10^{-19} \times 9.1 \times 10^{-31} \times V}}$ $5 \,??\frac{6.6 \times 10^{-34}}{5.4 \times 10^{-25} \sqrt{V}}$ $V=\left(\frac{6.6 \times 10^{-34}}{5.4 \times 10^{-25} \times 5 \times 10^{-10}}\right)^{2}$ $V=5.76$ volt