If the potential difference used to accelerate the electron is doubled, then by what factor does the de-Broglie wavelength of the electron beam change?

What is the de Broglie wavelength

Calculate the de-Brogile wavelength of an electron.

What is the de-Broglie wavelength of an electron with kinetic energy of 120 eV?

If photon and an electron have same de-Brogile wavelength then.

Calculate the ratio of the accelarating potential required to accelrate a proton and and alpha particle to have the same de-Broglie wavelength associated with them