Q.

A proton and an α-particle are accelerated from rest by 2V and 4V potential, respectively. The ratio of their de-Broglie wavelength is:               [2023]

1 4 : 1  
2 2 : 1  
3 8 : 1  
4 16 : 1  

Ans.

(1)

λ=hmv=h2mK=h2mqΔV

λαλp=mpVpqpmαVαqα

  λαλp=1×2×14×4×2=14

  λp:λα=4:1