Q.

An electron is accelerated from rest through a potential difference of V volt. If the de Broglie wavelength of the electron is 1.227×10-2 nm, the potential difference is     [2020]
 

1 10 V  
2 102 V  
3 103 V  
4 104 V  

Ans.

(4)

Given : de-Broglie wavelength of electron

    λ=1.227×10-2nm=0.1227Å

   λ=h2meV=12.27VÅ

We have, V=12.270.1227=100    V=104V.