Notice the numbered points on this diagram of a reflecting telescope. Which point represents the place where the starlight is in focus?
A) Point 1
B) Point 2
C) Point 3
D) None of the listed choices is correct. This telescope has no focus because there is a hole in the primary mirror.
A) Point 1
You might also like to view...
Web designers measure relative font sizes as a percentage of an em unit.
Answer the following statement true (T) or false (F)
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
A magnifying glass with focal length 15 cm is placed 10 cm above a stamp. The image of the stamp is located 30 cm above the magnifying glass
a. True b. False Indicate whether the statement is true or false
When a body moves in a straight line with increasing speed, the net force on it must be increasing
Indicate whether the statement is true or false