Why is the formulas to these two questions different? For finding the wavelength

Question

Why is the formulas to these two questions different? For finding the wavelength of an proton, we can just use the energy given, but for the electron we have to do square(2mE). Why is this?

An electron has a kinetic energy of 2.89 eV. Find its wavelength. .721 nm A photon has energy 2.89 eV. Find its wavelength. 429 nm Kinetic energy of an electron k = 6.07 eV = 6.07 eV(1.60 times 10 -19 J/eV) The de-Broglie wavalength of an electron is lamda = h/ 2mK = (6.626 times 10 -34 J.s)/ 2(9.11 times 10 -31 kg) (9.712 times 10 -19 J) = 4.98 times 10 -10 The wavelength of photon is lamda = hc/E = (6.626 times 10 -34 J.s) (3 times 10 8 m/s)/6.07eV (1.60 times 10 -19 J/eV) =2.05 times 10 -7 m =205nm

Explanation / Answer

This is completely depending on the nature of Photons and electrons. Photons have been considered of wave nature,so that formula has been used(which is generally used in finding the wavelength of anything which is of wave nature).

On the contrary, the nature of electron has been considered of particle nature.

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