A spherical metal dome of radius 15 cm is electrically charged. It has a positive charge of +2.5 μC distributed uniformly on its surface.

a. Calculate the electric field strength on the surface of the dome.
b. Explain how your answer to a would change at a distance of 30 cm from the surface of the dome.

2 answers

a)
1000000 v/m
a) From formula V=KQ/R and E=QV
We get E =KQ^2/R=(1.38×10^-23×(2.5×10^-6)^2)/0.15
E=5.75×10^-34 Vm^-1