1. The problem statement, all variables and given/known data Find the de Broglie wavelength for an electron with v=0.001c. Find the angular width of the central bright fringe in a double slit experiment, with the separation of the two slits d=50nm. 2. Relevant equations wavelength = h/mv d sin(theta)=n*wavelength 3. The attempt at a solution For the wavelength, I got 2.42x10^-9m. I think this sounds correct. Is my second equation for diffraction applicable here? I know that it is double slits so there will be interference and not just diffraction. If this equation is applicable, the my answer is 2*theta = 5.55 degrees. Or is there a specific equation for double slit that I should use?