If `E_(1) , E_(2) "and" E_(3)` represent respectively the kinetic energies of an electron , an alpha particle and a proton each having same de Broglie wavelength then :

Options

A. `E_1 gt E_3 gt E_2`
B. `E_2 gt E_3 gt E_1`
C. `E_1 gt E_2 gt E_3`
D. `E_1 = E_2 = E_3`

Answer

A

Explanation

According to relation , `E = 1/2 mv^2`
`sqrt( (2E)/(m)) = v rArr lamda = (h)/(sqrt(2mE))`
because `m_1 lt m_3 lt m_2`
so for same `lamda` , E_1 gt E_3 gt E_2`