- #1
Hypnos_16
- 153
- 1
Homework Statement
The Earth is surrounded by an electric field, pointing inward at every point. Assume a magnitude of E = 142N/C near the surface.
a) What is the net charge on the Earth?
b) How many excess electrons per square meter on the Earth's surface does this correspond to?
E = 142 N/C
Radius of Earth = 6.3781 km = 6,378,100 m
Homework Equations
Gauss's Law = EA
The Attempt at a Solution
So i know that i have to use Gauss's Law here. Which is simple the Electric Field, (given) and the area of the Earth which is found be 4πr2
Gauss's Law = EA
= (142) * (4πr2)
= (142) * (4π(6,378,100)2)
= (142) * (5.11e+14)
= 7.26e+16 C
however. After attempting that, i found it wasn't the right answer. Where did i go wrong?
i haven't attempted the second part since i need to know the first part. But i assume that to do it i would have to find the surface area of the Earth and divide it by the number i found in part a, then divide that by 1.6e-19 to find the number of electrons?