This preview shows page 1. Sign up to view the full content.
Physics 4322
Homework Set 2
January 24, 2012
Due: Tuesday, January 31, 2012
1. A wire has resistance
R
.
Determine the resistance of a wire twice the length and half the
diameter, assuming it is made from the same material.
2. A conducting sphere of radius
a
is embedded in a large volume filled with a material with
conductivity
.
The sphere is held a constant potential
V
o
with respect to the boundary, which
may be assumed to be at infinity.
Determine the current density
J
(
r
), the total current
I
, and the
resistance
R
.
(Hint: Laplace’s equation for
V
must be satisfied.)
3. Two concentric conducting spherical shells having inner and outer radii
a
and
b
, respectively,
are separated by a weakly conducting material of conductivity
.
(a) If the potential difference
between the spheres is
V
, what current
I
exists between the spheres? (b) What is the resistance
R
between the shells?
4. Suppose the conductivity of a material between two concentric cylinders is
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 02/20/2012 for the course PHYS 1101 taught by Professor Lowellwood during the Fall '10 term at University of Houston.
 Fall '10
 LOWELLWOOD
 Resistance, Work

Click to edit the document details