Protons and `alpha`-particles have the same de Broglie wavelength. What is same for both of them?

Proton and alpha -particle have the same de-Broglie wavelength. What is same for both of them ?

Proton and alpha particle have the same deBroglie wavelength. Which one is the same for both of them ?

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

A proton and alpha particle have the same K.E. Their de Broglie wavelengths are in the ratio

Calculate the ratio of the accelerating potential required to accelerate (i) a proton and (ii) and alpha particle to have the same de-Broglie wavelength associated with them.