Question

1. If a surface is a 10 meter by 10 meter plane lying in the y-z plane, what is the vector representing the area of the plane?

2. If a sphere of radius 2 meters is placed in a uniform electric field of 3 N/C, what is the net flux through the sphere?

3. Show how Gauss's Law can be used to derive Coulomb's law for a single charge. Explain any simplifications and draw your Gaussian surface.

Answer 1

100 in the x direction or 100 i

the cross section hit perpendicular to the field is pi r^2

draw sphere centered at origin around charge Q at origin
By symmetry E is constant over surface of sphere at any radius r (surface area 4 pi r^2)
net flux through surface of sphere = E*(4 pi r^2) = Q /eo
so
E = Q/(4 pi r^2 eo)
done