Sunspot numbers follow a seven-year cycle
a. True
b. False
Indicate whether the statement is true or false
False
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Answer the following statement(s) true (T) or false (F)
1. Imagine a neutral atom near an infinite charged plane. The neutral atom will be polarized by the plane’s field.
Which of the outer planets has rings?
A. Neptune B. Uranus C. Saturn D. Jupiter E. All of the outer planets have a ring system.
A 0.3-cm-thick aluminum plate has rectangular fins 0.16 x 0.6 cm, on one side, spaced 0.6 cm apart. The finned side is in contact with low pressure air at 38°C and the average heat transfer coefficient is 28.4 W/(m2 K). On the unfinned side water flows at 93°C and the heat transfer coefficient is 284 W/(m2 K). (a) Calculate the efficiency of the fins (b) calculate the rate of heat transfer per unit area of wall and (c) comment on the design if the water and air were interchanged.
GIVEN
FIND
(a) The fin efficiency (?f)
(b) Rate of heat transfer per unit wall area (q/Aw)
(c) Comment on the design if the water and air were interchanged
ASSUMPTIONS
Width of fins is much longer than their thickness
The system has reached steady state
The thermal conductivity of the aluminum is constant
SKETCH
If light from a distant star passes close to a massive body, the light beam will:
A) bend towards the star due to gravity. B) continue moving in a straight line. C) change color to a shorter wavelength. D) slow down. E) accelerate due to gravity.