Question

A 2.0-Coulomb bead is given 20 Joules of electric potential energy by lifting it from the "ground" to point A. If a second bead with twice as much charge, 4.0 Coulombs, is lifted through the same distance, intuitively, how much electric potential energy do you expect it to have at point A?

Answer 1

Answer:

40 J

Explanation:

$c_1$ = 4 C

$c_2$ = 2 C

$U_1$ = 20 J

The potential energy is directly proportional to the charge of the particle

$U\propto c$

$\dfrac{U_2}{U_1}=\dfrac{c_2}{c_1}\\\Rightarrow U_2=\dfrac{U_1c_2}{c_1}\\\Rightarrow U_2=\dfrac{20\times 4}{2}\\\Rightarrow U_2=40\ J$

The potential energy expected is 40 J