1. The problem statement, all variables and given/known data Determine at what energy, in electron volts, the Nonrelativistic expression for the de Broglie wavelength will be in error of 1% for an electron. 2. The attempt at a solution For the error to be 1%, that means that the classical wavelength/relativistic wavelength will be 99% or 0.99. Whe you divide the formula for classical de Broglie wavelength and relativistic de Broglie wavelength, it equals gamma, however, gamma cannot ever be below 1. Thus gamma=0.99 is a contradiction. I appreciate your help, Thanks.