Posted by **How many excess electrons must be distributed unif** on Wednesday, February 10, 2010 at 12:31pm.

How many excess electrons must be distributed uniformly within the volume of an isolated plastic sphere 28.0 in diameter to produce an electric field of 1500 just outside the surface of the sphere?

- physics -
**drwls**, Wednesday, February 10, 2010 at 1:43pm
1500 whats? Newtons per Coulomb?

Use Gauss' law.

The product of the area (pi D^2/6) and the E-field at the surface is equal to the total charge inside the sphere divided by the constant "epsilon-zero". Find that constant and compute the total charge. Divide that charge by the electron charge (e) to get the number of excess electrons.

It is not necessary that the electrons be distributed uniformly, as long as there is spherical symmetry.

- physics (correction) -
**drwls**, Wednesday, February 10, 2010 at 8:12pm
The surface area of a sphere is, of course,

A = 4 pi R^2 = pi D^2,

NOT what I wrote.

I was thinking of the volume, and then got the exponent wrong.

Use the area in Gauss' Law.

## Answer this Question

## Related Questions

- physics - (a) How many excess electrons must be distributed uniformly within the...
- PHYSICS - When a conducting sphere is charged positively, initially the charge ...
- pre ap physics - ** When s conducting sphere is charged positively, initially ...
- + --> a sphere --> (+) - Multiple Choice Help: ** When s conducting sphere...
- Physics - Consider an insulating sphere with 10 microCoulombs of charge ...
- physics - Consider an insulating sphere with 10 microCoulombs of charge ...
- Physics - 1)When two bodies are charged, the total charge before and after ...
- Physics please HELP - Consider an insulating sphere with 10 microCoulombs of ...
- physics - When two bodies are charged, the total charge before and after ...
- Physics - The electric field at a distance of 0.150 m from the surface of a ...

More Related Questions