How have astronomers discovered planets orbiting a star beyond the Sun?
A. They can see the planet brighten as it passes in front of its parent star.
B. They have bounced radar off them.
C. They can be detected by the slight gravitational tug that they exert on their parent stars.
D. So far, no planets have been discovered around any other stars.
Answer: C
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An ______style only affects the content within the tags in which it appears.
A. inline B. internal C. interface D. intermittent
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
Thin Lenses: An object is placed 9.5 cm in front of a convex lens with a focal length of magnitude 24 cm.(a) Where is the image formed and how far is it from the lens?(b) What is the magnification produced by the lens?
What will be an ideal response?
Inductive reactance XL is given by
A.
B.
C.
.D.
E.