Electron accelerated through field

[QuantumKing]

A beam of electrons is accelerated through a field of a different potential which produces a velocity of 5,45x10^7 m/s. The mass of an electron being 9,11x10^(-31) kg, what would be the wave length of the electron beam?

A question i encountered when doing homework, i need some help with this one..anyone? thanks

 

[Galileo]

So you need some relation between the mass, velocity and wavelength of your electrons. Did you learn about anything that relates these?

 

[QuantumKing]

would it be...
mc^2=hf
(5.45x10^7)(3x10^8)^2=(6.626x10^-34)(f)...find the frequency and therefore the wave length?...id like to know wether i should be finding the electron's rest energy, kinetic energy..or should i use (mc^2)/(1-v^2/c^2)^1/2?..(lorentz transformation of energy)

 

[QuantumKing]

i got 0,0013 nanometers