GEOG 1302 Lecture 4: Cultural Regions

By substituting T=T(m)+A(s)exp(-z/d)sin[(2pi/P)(t-t(m))] intodT/dt=(d/dz)[(k/C(s))(dT/dz)]=(d/dz)[a(h)(dT/dz)], verify that theformer is a solution of Fourier's equation of heat conductionthrough a homogenous soil medium, and then, derive the expressionfor the ground heat flux.

T(m)-->the mean temperature of the surface
A(s)-->amplitude
P-->period
t(m)--> the time when T(s)=T(m)

Two identical infinite uniformly charged sheets are parallel
to the x-y plane. One sheet has a positive surface density ofcharge and
located distance d in the positive z direction from the origin. Theother one
has the same charge density, but loctaed distance d in the negativez direction
from the origin. Use superposition to find the electric field(magnitude and
direction) due to the two sheets in three regions: (a) z > d,(b) -d < z < d
and (c) z < -d.

<DIV>what is the maximum value of the magnetic field at adistance 1 m from a 100 W light bulb?<BR>a. 0.1µT</DIV>
<DIV>b. 0.2 µT</DIV>
<DIV>c. 0.3 µT</DIV>
<DIV>d. 3 µT</DIV>