# Gauss's Law - point charge and charged sphere.

Katana750

## Homework Statement

A point charge q1 = -9.7 μC is located at the center of a thick conducting shell of inner radius a = 2.3 cm and outer radius b = 4.5 cm, The conducting shell has a net charge of q2 = 1.4 μC.

1) What is Ex(P), the value of the x-component of the electric field at point P, located a distance 8.2 cm along the x-axis from q1?

E=K*q/r^2

## The Attempt at a Solution

I'm honestly not sure where to start. I tried computing Eq1 at the inner edge of q2, then determining the resulting E at the outer edge of q2 then using that q value and computing E from the outer edge to P. Needless to say I didn't get the right answer.

Also, I'm new here...Last year (phys 1) I got by well enough to get a B+ in the class, but once we got beyond statics and dynamics and rotional forces (i.e. once we got to electrical/magnetic and hydrostatic forces) I was kind of lost. This year (phys 2) I'm planning to stay on top of things and actually UNDERSTAND the material, not just get a passing grade. Hence the reason I joined this forum - I apologize in advance for any dumb questions - if you see it on here rest assured that I spent at least an hour trying to figure it out on my own.

Any help is greatly appreciated!

voko
The field by any spherical conductive shell is the same as that of a point at its center with its total charge.

Katana750
The field by any spherical conductive shell is the same as that of a point at its center with its total charge.

Can you explain that in terms of the equations?

voko
If the shell has total charge Q, then the electric field at R from its center is E = K * Q / R^2.

Observe that this effectively means, in this problem, you have charges q and Q at the center. How would their fields interact?