Question

A proton and an α-particle are accelerated through the same potential difference. Which one of the two has less kinetic energy? Justify your answer.

Answer 1

The kinetic energy is related to accelerating potential as

K.E. = eV

∴ K.E._p = e_pV

And, K.E._α = e_αV

`:.(K.E._p)/(K.E._alpha)=e_p/e_alpha`

Since, the charge on proton is less than that on alpha particle,

K.E._p <  K.E._α for the same potential difference.