Electron Emission

When an electron is accelerated through a voltage , the wavelength of the emitted radiation is related to the energy acquired by the electron. The energy acquired is given by: where is the charge of the electron and is the voltage. The energy of the electron is inversely proportional to the wavelength, as given by: where is Planck's constant, is the speed of light, and is the wavelength. From this, we can derive that the wavelength is inversely proportional to the accelerating voltage: Given that the initial wavelength for a voltage of 480V is , for a voltage of 120V, the wavelength is:
Thus, the new wavelength when the electron is accelerated through 120V is .