# Gauss's law?

1. Apr 6, 2015

### Jess155

1. The problem statement, all variables and given/known data
In a particular region of the earth's atmosphere, the electric field above the earth's surface has been measured to be 148 N/C downward at an altitude of 260 m and 165 N/C downward at an altitude of 410 m. Calculate the volume charge density of the atmosphere, assuming it to be uniform between 260 and 410 m. (Hint: You may neglect the curvature of the earth. Why?)

2. Relevant equations
volume charge density = Q/V

3. The attempt at a solution
No clue where to even start. And why they gave me two altitudes and E fields

2. Apr 6, 2015

### Halo CX

You can imagine a box shaped structure whose height is that of the difference between the given altitudes and the upper and lower surfaces have area A. Then calculate the total electric flux through the box. Assume a charge density $$\rho$$ and calculate total charge inside the box. Then finally, use Gauss's law.

3. Apr 6, 2015

### SammyS

Staff Emeritus
Hello Jess155. Welcome to PF !

You titled the thread, "Gauss's law?" .

That's a good place to start.