1. The problem statement, all variables and given/known data In a diffraction experiment in which electrons of kinetic energy 110 eV are scattered from a crystal, a first maximum in the intensity of the scattered electrons occurs at an angle θ=10.7 a) How many peaks will there be in the interference pattern? b) What is the spacing between the atom planes? 2. Relevant equations 2d sinθ = nλ λ = h/p = h/√(2m KE) 3. The attempt at a solution From the kinetic energy of the electron I found the wavelength to be 1.17*10^-10 m , then I don't understand how to use it in that equation, I believe n is the number of peaks, and d is the spacing, so how would I solve this equation while two variables are missing?