- #1
timetraveller123
- 621
- 45
Homework Statement
Homework Equations
The Attempt at a Solution
a) charge induced is
##\frac{-q_i}{4 \pi r_i^2} = \sigma_i##
##\frac{q_a + q_b}{4 \pi R^2} = \sigma_R##
b) field outside is ##\frac{k (q_a + q_b)}{r^2}##
c)i naively applied gauss law to get field within each cavity as
##\frac{k q_i}{r_i^2}##
d) i was assuming the only field in the cavity is due to charge itself only and due to induced charge on the inner surface hence force = 0 which is correct
but part e confuses me
e)
the provided answer
how could ##sigma_r## change and still have the ##\sigma_a## and ##sigma_b## constant while the conductor is neutral
furthermore this another text states
"The field inside the cavity depends only on the charge q and on the charge that gets induced on the inner surface of the cavity."
how could the induced surface charges affect the field inside if they are not included in the Gaussian surface