[Noor]

Q.What is the wavelength of a beam of electron traveling at 2 x 10^6 cm/s?

A: 3.64 x 10 ^ -6

Now we have the mass of electron: 9.109 x 10^-31 kg

and we have the formula: E= hc/lambda  and/or c= v x lambda

but I am not exactly sure of how to solve it? Do we need the mass of an electron? How do you go about it? The answer is above, but I am not sure of the way to answer it. Immediate help would be GREATLY APPRECIATED!

[LQ43]

those equations are for PHOTONS - not electrons which are MATTER

try lambda =  h/mv   DeBroglie wave equation for matter