Q.

An electron accelerated through a potential difference V1 has a de-Broglie wavelength of λ. When the potential is changed to V2, its de-Broglie wavelength increases by 50%. The value of (V1V2) is equal to                [2023]

1 3  
2 94  
3 32  
4 4  

Ans.

(2)

K.E.=P22m, P=hλ

eV1=(hλ)22m

eV2=(h1.5λ)22m

V1V2=(1.5)2=94