A particle is moving three times as fast that of an electron. The ratio of de - Broglie wavelength of particle to that of the electron is 1.83×10–4. Then the particle is

The mass of neutron and proton is the same and equal to 1.6 x 10-27 kg. While mass of electron is 9 x 10-31kg. It is moving three times faster than electron. The degroglie wavelength is given by λ = h/p. hence λ1λ2= p2p1. which is satisfied by both neutron and proton