Question

A particle of charge Q and mass m is accelerated from rest through a potentialdifference V, attaining a kinetic energy K. What is the kinetic energy of a partical of charge2Q and mass m/2 that is accelerated fromrest through the same potential difference?
a) K/4
b) K/2
c) K
d) 2K
e) 4K

Answer 1

Hi there!

Recall the equation for work given a potential difference and charge:
$\large\boxed{W = qV}$

W = Work (J)
q = charge (C)
V = Potential difference (V)

The work is equivalent to the change in KINETIC ENERGY, and only depends on the particle's charge and the potential difference that it experiences. Mass has no impact on this.

Thus:

$W' = (2Q)(V) = 2W$

This is equivalent to:

$\large\boxed{2W = \text{ d) } 2K}}$