The hot spots in a double-lobed radio source
a. appear to coincide with the location of the central galaxy responsible for the jets.
b. are where hot excited gas interacts with the intergalactic medium.
c. are only found near quasars.
d. produce enough visible energy to be imaged at visible wavelengths.
e. are always perpendicular to each other.
Question 2A(n) _________ is a collection of 10 to 1000 stars in a region about 25 pc in diameter. The stars in the collection are typically quite young.
a. Herbig-Haro object
b. globular cluster
c. open cluster
d. giant cluster
e. supernova
Question 3In the double-exhaust model, the radio lobes of a radio galaxy are inflated by
a. jets of excited gas flowing from the central galaxy.
b. jets of high-energy sound waves flowing from the central galaxy.
c. a disk of ionized material that orbits very near a supermassive black hole.
d. dark clouds of very cold gas and dust.
e. None of the other choices are correct.
Question 4Giant and supergiant stars are rare because
a. they do not form as often as main-sequence stars.
b. the star blows up before the giant or supergiant stage is reached
c. the giant or supergiant stage is very short.
d. the giant or supergiant stage is very long
Question 5All __________ galaxies are spiral galaxies that have small, luminous nuclei.
a. active
b. radio
c. Seyfert
d. double-lobed radio
e. blazar
Question 6In degenerate matter
a. pressure depends only on the temperature.
b. temperature depends only on density.
c. pressure does not depend on temperature.
d. pressure does not depend on density.
e. temperature depends only on density and does not depend on temperature.
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