Q.

A proton moving with one tenth of velocity of light has a certain de Broglie wavelength of λ. An alpha particle having certain kinetic energy has the same de-Broglie wavelength λ. The ratio of kinetic energy of proton and that of alpha particle is                    [2023]

1 2 : 1  
2 4 : 1  
3 1 : 2  
4 1 : 4  

Ans.

(2)

KE=p22m=h22mλ2

KEpKEα=mαmp=4:1