Question

5. Consider a point charge at the center of a spherical Gaussian surface. Explain why of why not the electric flux changed (a) if the Gaussian surface is replace with a cube having the same volume as the sphere, (b) if the cube has 1/2 the volume of the sphere, (c) if the charge is moved off-center from the original sphere yet remains inside, (d) if the charge is moved just outside the sphere, (e) if a second charge is placed near, yet outside, the original sphere, (f) If a second charge is placed inside the sphere?

Answer 1

Electric flux is total field lines passing through the surface, and number of field lines does not depend on surface area or volume of the Gaussian surface but it depends on the amount of charge.

a) flux will not change as the charge is same.

b) flux will not change as the charge is same.

c) flux will not change as the charge is same and still inside.

d) flux will be zero as there is no charge inside.

e) flux will not change as flux due to outside charge is zero.

f) flux will change, now flux will be due to both the charges.