Question

Part A: How many excess electrons must be distributed uniformly within the volume of an isolated plastic sphere 26.0cm in diameter to produce an electric field of 1500 N/C just outside the surface of the sphere? Part B: What is the electric field at a point 13 cm outside of the surface of the sphere?

Answer 1

Q = 28.17 x 10⁻¹⁰ C

E= 375 N/C

Step-by-step explanation:

Let Q be the charge on plastic sphere.

Field on the surface =k x charge / radius²

Putting the values we get

`1500=(9*10^9* Q)/((13*10^(-2)^2))`

Q = 28.17 x 10⁻¹⁰ C

No of electrons = Charge / charge on one electron

=
`(28.17* 10^(-10))/(1.6*10^(-19))`

= 7 x 10¹⁰

Electric field at 13 cm

=
`(9*10^9*28.17*10^(-10))/(26^2*10^(-4))`

E= 375 N/C