Question

A proton and an electron move between two points having a potential difference V.
(a) Which gains more energy?
(b) Define electron volt.
(c) How is 1 e V and 1 MeV related to joule?
(d) Write the dimensional formula of electrostatic potential.

Answer 1

(a) Both gain the same energy
Work done = energy gain = Potential difference x Charge
The p.d and charge are the same for each.

(b) One eV is the kinetic energy acquired by an electron accelerated on an electric field of p.d. one volt

(c) 1 MeV= 106 eV = 1.6 x 10-13 J
1 eV = 1.6 x 10-19 J

(d) [V] = [\(\frac { W }{ q }\) ]
= \(\frac{\left[\mathrm{ML}^{2} \mathrm{~T}^{-2}\right]}{[\mathrm{I} \times \mathrm{T}]}\)
= M1L2T-3I-1]