Absorption lines due to the interstellar medium indicate that some components of the interstellar medium are cold and of a very low density because
a. the lines are blue shifted.
b. the lines are red shifted.
c. the lines are extremely broad.
d. the lines are extremely narrow.
e. the lines are much darker than the stellar lines.
d
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Since evaporation of water from reservoirs is an important water loss mechanism, especially in dry climates, it is important to reduce losses. What measures could you suggest for reducing such evaporation? Are any of these actually feasible?
What will be an ideal response?
A student finds three resistors in the lab: a two ohm, a five ohm, and a 10 ohm resistor. The smallest value of resistance that the student can make using any one or any combination of the three resistors is ________ ohms.
Fill in the blank(s) with the appropriate word(s).
You have measured Doppler shifts to plot velocity curves for two otherwise identical stars. Star A has a period of 6 months and Star B has a period of 1 year. What can you say about the planets causing the motions of these stars?
A) Star A's planet is more massive than Star B's planet. B) Star A's planet must orbit closer in than Star B's planet. C) It is impossible to say anything about the planets orbiting these stars. D) Star B must have a planet like Earth.
Consider the curve f(x) = A cos(2?x/?). The wavelength of the wave will be:
a.
the distance 0 to A.
b.
twice the distance 0 to A.
c.
the distance x2 to x3.
d.
twice the distance x2 to x3.