An electron and proton have the same de-Broglie wavelength. Then the kinetic energy of the electron is

Options

A. more than that of a proton
B. equal to that of a proton
C. zero
D. less than that of a proton

Answer

A

Explanation

`lambda_(de)` Broglie `=h//p`
`therefore` As the wavelenght are the same, `(h)/(m_ev_1) = (h)/(m_pv_2)`
`rArr m_eV_1 = m_pv_2`
Kinetic energy of the electron `= (1)(2m_e) (m_ev_1)^2`
Kinetic energy of the proton `=(1)/(2mp)(m_pV_2)^2`
Therefore the kinetic energy of electron is more than that of the proton as the proton is heavier than the electron.