Electromagnetism - Gauss' Law

Five positive charges of magnitude q are arranged symmetrically around the circumference of a circle of radius r. What is the magnitude of the electric field at the center of the circle? (k = 1/4πε0)

A. 0
B. kq/r2
C. 5kq/r2
D. (kq/r2) cos (2π/5)
E. (5kq/r2) cos (2π/5)
(GR0177 #09)
Solution:

Gauss’ Law:  

There is no qenc inside the Gaussian surface → E = 0  

Answer: A

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