What is the kinetic energy of particles with a de Broglie wavelength of 0.50 nm?

[thatoneguy123]

Find the kinetic energy of the following particles that each have a de Broglie wavelength of 0.50 nm.?

(a) photons
____eV = 2480eV
(b) electrons
____eV
(c) neutrons
____eV
(d) α particles
____eV

i know E= hc/wavelength which = a and after that I am stuck i know that the wavelength = h/p but i don't know how to solve the others with this

 

[thatoneguy123]

i found be by taking hc/ lamda squared and dividing it by the momentum squared

 

[grzz]

momentum p,
p = h/\lambda

total energy E :
E^{2} = p^{2}c^{2} + m_{o} ^{2}c^{4}

KE = E - m_{o}c^{2}