Question

The two lines A and B in fig. show the photo electron of de Broglie wavelength `(lamda)` as a function of `(1)/(sqrtV) `(V is the accelerating potential) for two particles having the same charge. Which of the two represents the particle of heavier mass?

Answer 1

When a charged particle of charge q, mass m is accelerated under a potential difference V, then de- Broglie wavelength associated with particle is,
`lambda=h/(sqrt(2mqV))`
If V is constant, then `lambdaprop 1/(sqrtm)`
From graph, `lambda_Bgtlambda_A`, so `m_Agtm_B`. It means the particle A is of heavier mass.