Question

1) A point charge q1 = 4.35 nC is located on the x-axis at x = 2.15 m , and a second point charge q2= -6.45 nC is on the y-axis at y = 1.15 m

Part A What is the total electric flux due to these two point charges through a spherical surface centered at the origin and with radius r1 = 0.540 m ? ''

Part B What is the total electric flux due to these two point charges through a spherical surface centered at the origin and with radius r2 = 1.45 m ?

Part C What is the total electric flux due to these two point charges through a spherical surface centered at the origin and with radius r3 = 2.45 m ?

Answer 1

(a) Electric flux = charge enclosed / e_o where e_o is permittivity and is equal to 8.85e-12

if we draw a circle of radius 0.54 m centered at origin then we will observe that no charge is enclosed, therefore flux must be zero.

so, Electric flux = 0

(b) Now, again draw a circle of radius 1.45 m centered at origin, we will see that it encloses only the second point charge,

so, Electric flux = - 6.45e-9 / 8.85e-12

Electric flux = - 728.81 Vm (negative sign shows that flux is entering)

(c) Now for a circle of radius 2.45, it enloses both charges,

so net charge is = 4.35 - 6.45 = -2.1 nC

Electric flux = - 2.1e-9 / 8.85e-12

Electric flux = - 237.29 Vm