PHYSCI 13 Lecture 9: Physci 13 lec 9

<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>

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)

If you have a concave mirror, how far must you place the object? in order to get an upright, enlarged image?

d= distance from the object to mirror; f=mirror's focal length

d < f

d = f

d > f

d > 2f

more information is needed