energy (in ev)=12400/wavelength(in A)
this formula is applicable to all the particles like photon electron, proton or is specific to any one particle?

Dear Student,
This formula is actually 
energy=hc/$\lambda$  where value of plancks constant (h) and speed of light(c) are put. 
This formula is applicable for photons (also for other particles if they move with speed of light).
Regards