The equation $\lambda=\frac{1.227}{\mathrm{x}} \mathrm{nm}$ can be used to find the de-Brogli wavelength of an electron. In this equation x stands for Where, $\mathrm{m}=$ mass of electron $\mathrm{P}=$ momentum of electron $\mathrm{K}=$ Kinetic energy of electron $\mathrm{V}=$ Accelerating potential in volts for electron