Lets say I have a positively charged conducting sphere of Q. The electric field outside the sphere is
$$E = \frac Q{4\epsilon\pi r^2}$$$$E = \frac Q{4\epsilon\pi r^2}.$$
Now suppose this sphere is enclosed inside another hollow conducting sphere of -Q charge. By Gauss law, the electric field is still the same?
Won't the negatively charged outer sphere reinforce the electric field, causing it it be larger?
In another example,
The field from a infinite sheet of charge is
$$ E = \frac \sigma{2\epsilon} $$$$ E = \frac \sigma{2\epsilon}. $$
But the field between 2 oppositely charged infinite sheets is
$$ E = \frac \sigma{\epsilon} $$$$ E = \frac \sigma{\epsilon}. $$
Why is this not the case above?
