Question

A 1.00~\text{cm}1.00 cm diameter plastic sphere, used in a static electricity demonstration, has a charge of 45.2~\text{pC}45.2 pC uniformly distributed on its surface. What is the potential at its surface (or just barely above it)?

Answer 1

Answer:

$16272 J/C$

Step-by-step explanation:

Parameters given:

Diameter of sphere = 1cm

Radius of sphere = 0.5cm = 0.005m

Charge of sphere = 45.2 pC = $4.52 * 10^{-11} C$

Electric potential at a distance, r, from a charge, Q,  is given as

$V = \frac{kQ}{r}$

where

k = Coulombs constant

The charge of a sphere is always located at the center of the sphere. This means that the distance between the charge of the sphere and its surface is the radius.

Hence, Electric potential is:

$V = \frac{9 * 10^9 * 4.52 * 10^{-11}}{0.005^2} \\\\\\V = \frac{0.4068}{0.000025}\\ \\\\V = 16272 J/C$