Q.

The de-Broglie wavelength associated with an electron accelerated through a potential difference V is λe and the de-Broglie wavelength associated with a proton accelerated through the same potential difference is λp. If their corresponding masses are me and mp, respectively, then the ratio of their de-Broglie wavelengths (λeλp) is _______.         [2026]

1 mpme  
2 memp  
3 mpme  
4 (mpme)2  

Ans.

(1)

de-Broglie wavelength,  λ=h2mqV∝1m

So,  λeλp=mpme