Mastering Physics: Exercise 22.3

Mastering Physics: Exercise 22.3

You measure an electric field of 1.32×10^6 N/C at a distance of 0.156 m from a point charge. There is no other source of electric field in the region other than this point charge.

Part A

Question: What is the electric flux through the surface of a sphere that has this charge at its center and that has radius 0.156 m ?

Answer: 

Φ =  E⋅A 

= 1.32×10^(6) N/C × 4π(r^2)

=1.32×10^(6) × 4π(0.156)^2

= 4.04×105  N⋅m^2/C  

Part B

Question: What is the magnitude of the charge?

Answer: 

Φ = q_enclosed/(ϵ_0)

q_enclosed = 4.04×10^(5) × 8.85 ×10^(-12)

q =  3.57×10^(−6)  C