If the speed of an electron is v and the speed of another particle is 3v, ratio of the de Broglie wavelength of the electron to that of the particle is `(10^4)/(8.13)`. Is the particle a proton or an `alpha`-particle? Justify your answer.

Explanation

de Broglie wavelength, `lamda = (h)/(mv)` [ h = Planck's constant]
`:.` For the electron and the other particle,
`(lamda_(1))/(lamda_(2)) = (m_(2))/(m_(1)).(v_(2))/(v_(1)) or, (m_(2))/(m_(1)) = (lamda_(1))/(lamda_(2)).(v_(1))/(v_(2)) = (10^(4))/(8.13) xx (v)/(3v) = (410)/(1)`
`:.` The other particle is 410 times heavier than an electron. If is neither a proton nor an `alpha`-particle