Perfect absorbers of electromagnetic radiation are also perfect emitters
Indicate whether the statement is true or false
T
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At what angle above the horizon would the sun appear if its reflected light from a lake, viewed at the same time, were completely polarized? (n water = 1.333)
A. 53.12 
B. 36.88 
C. 48.75
D. 41.25
E. 23.52
In order for a telescope to produce a large magnification one would select lenses of
A. short focal length for both objective and eyepiece. B. large focal length for the objective and short focal length for the eyepiece. C. short focal length for the objective and long focal length for the eyepiece. D. large focal length for both objective and eyepiece.
Equipotential Surfaces: The equipotential surfaces for two spherical conductors are shown in the figure, with the value of potential marked on the line for each surface.(a) If the distance between points A and B is 2.5 cm what is the approximate intensity of the electric field between these two points?(b) If the distance between points C and D is 2.5 cm what is the approximate intensity of the electric field between these two points?
Fill in the blank(s) with the appropriate word(s).
including a contact resistance of 0.1 K/W at each of the interfaces. but assume that instead of surface temperatures, the given temperatures are those of air on the left and right sides of the wall and that the convective heat transfer coefficients on the left and right surfaces are 6 and 10 W/(m2K), respectively.
GIVEN
• Composite wall
• Thermal conductivities
? kA = 70 W/(m K)
? kB = 60 W/(m K)
? kC = 40 W/(m K)
? kD = 20 W/(m K)
• Air temperatures
? Left side (TA?) = 200°C
? Right side (TD?) = 50°C
• Contact resistance at each interface (Ri) = 0.1 K/W
• Convective heat transfer coefficients
? Left side ( cA h ) = 6 W/(m2 K)
? Right side ( cD h ) = 10 W/(m2 K)
FIND
(a) Rate of heat transfer through the wall (q) (b) Temperatures at the interfaces
ASSUMPTIONS
• One dimensional, steady state conduction
SKETCH
