Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

a) The electric field at a distance of 2 mm from the center of a charged conduct

ID: 2010661 • Letter: A

Question

a) The electric field at a distance of 2 mm from the center of a charged conducting sphere of

radius 1 mm is 480 N/C. What is the electric field at a distance of 6 mm from the center of the sphere?

Find the electric flux through the spherical Gaussian surfaces of radius 2 mm and 6 mm

whose centers coincide with that of the charged sphere.

(b) At a distance of 2 mm from the axis of a very long conducting cylinder with radius 1 mm,

the electric field is 480 N/C. What is the electric field 6 mm from the axis of the

cylinder?

(c) What is the electric field 0.5 mm from the axis of the cylinder?

(d) Assume that the cylinder is now shrunk along its radius so that it becomes a straight line

that coincides with its axis, and carries the same total charge. What will be the electric

field 0.5 mm from this charged line? Is it different from the result in the last step? Justify

your answer.

(e) At a distance of 2 mm from a very large uniform sheet of charge, the electric field is 480N/C. What is the electric field 1.2 cm from the sheet? What is the charge density on the sheet? What is the force on a proton when it is 1.2 cm from the sheet? A proton carries a charge of -e.

Explanation / Answer

For part a the relationship is E1/E2=R2/R1. That would yield 53.3N/C