Question about Electric Field lines (MCQ)

[Helmy]

*This is a question in an assignment that i have to submit.

1. Homework Statement

Two imaginary spherical surfaces of radius (R) and (2R) respectively surround a positive point charge (Q) located at the center of the concentric spheres. What is the number of electric field lines (N2) going through the sphere of radius (2R) compared to the number of field lines (N1) going through the sphere of radius (R)?
2. Given Answers:
1- N2 = 8 N1
2- N2 = 1/64 N1
3- N2 = 64 N1
4- N2 = N1
5- N2 = 1/8 N1
PS:
-so i integrated E.dA according to Gauss's law and substituted both radii and they gave the same result which is q/ϵ0, So when compared the two spheres have the same amount of flux, and knowing that the flux is proportional to number of field lines this means that both spherical surfaces have the same number of field lines passing through them so N1 = N2 right?

 

[BvU]

Hello Helmy,

Please use the template in its complete form. Read the guidelines to understand why we can't help you this way.

 

[BvU]

http://www.physicsclassroom.com/class/estatics/Lesson-4/Electric-Field-Lines
(I have to run...)