Unformatted text preview: lectric field
to be zero at
a distance r
from the
center of the
cylinder the
total charge
inside a
Gaussian
cylinder of
radius r must
be zero. So,
calculate
charge inside
as a function
of radius and
solve for the
radius where
charge is
zero. 11. A cylindrically symmetric charge distribution has a volume charge density that depends
r2
on the radial position, r, as follows: (r ) 0 (1 2 ) , where is the charge density at
a
the central axis and "a" is just a size constant. At about what nonzero radius is the
electric field equal to zero?
A) 1.4a
B) 1.8a
C) 0.6a
D) 0.8a
E) 1.2a 12. What is the electric potential at B relative to a potential of zero an infinite distance away?
When I made "wrong" answer choices for this problem I
accidentally created one that is actually correct. You get full
credit for choosing either of the two correct answers
(here E is correct if you put origin on right side of bar and
make x positive going left. Its a weird looking coordinate
system, but it make...
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 Spring '08
 DaveWinn
 Physics, Charge, Electric charge, coulombs, rdx, David Winn

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