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Question

Physics Question on de broglie hypothesis

The kinetic energy of an electron is 5eV5\,\,eV . Calculate the de-Broglie wavelength associated with it ( h=6.6×1034Jsh=6.6\times {{10}^{-34}}\,\,Js , me=9.1×1031kg{{m}_{e}}=9.1\times {{10}^{-31}}kg ):

A

5.47 ??/div>

B

10.9 ??/div>

C

2.7 ??/div>

D

none of these

Answer

5.47 ??/div>

Explanation

Solution

Wavelength associated with an electron λ=h2mE\lambda =\frac{h}{\sqrt{2 m E}} =6.6×10342×9.1×1031×5×1.6×1019=\frac{6.6 \times 10^{-34}}{\sqrt{2 \times 9.1 \times 10^{-31} \times 5 \times 1.6 \times 10^{-19}}} $=5.47 \times 10^{-10} m =5.47 ,??