Certain substance emits only the wavelengths `lamda_1,lamda_2,lamda_3` and `lamda_4` when it is at a high temperature, it will absorb only the following wavelengths

The de-Broglie wavelength lamda

Momentum of a photon of wavelength lamda is

lamda_1, lamda_2, lamda_3 are the first 3 lines of balmer series. Find lamda_1//lamda_3

Neglecting the mass variation with velocity , the ratio of the wavelength ((lamda_e)/lamda_p) associated with an electron (lamda_e) having a kinetic energy E and wavelength associated with a Photon (lamda_p) having kinetie energy 4E is