Question 1

The hydrogen Balmer line H β\betaβ  has a wavelength of 486.1 nm in the laboratory.It is observed in a quasar at 2430.5 nm.What is the red shift of this quasar?

Accepted Answer

A)   5
B)   0.5
C)   0.25
D)   4
E)   1944.4  D

Question 2

The hot gas of a radio lobe could be held together by

Accepted Answer

A)   collision with the intergalactic medium.
B)   the lobe's magnetic field.
C)   the lobe's gravitational field.
D)   the angular momentum of the galaxy.
E)   the shock wave from a nearby quasar.

Question 3

Astronomers can estimate the mass of the black hole at the center of the active galaxy M87 from the

Accepted Answer

A)   orbital speed of the gas disk around it.
B)   the distance of the orbiting gas from the center.
C)   both a and B

Question 4

A(n) ____ is observed if our line of sight is parallel to the plane of the dense disk of an active galactic nucleus.

Accepted Answer

A)   blazer
B)   Type 1 Seyfert
C)   Type 2 Seyfert
D)   superluminal expansion
E)   quasar

Question 5

Jet-shaped regions of radio and optical emission have been observed in

Accepted Answer

A)   quasars.
B)   radio galaxies.
C)   the 3° Kelvin radiation.
D)   both a and

Question 6

We suspect that quasars are the active centers of galaxies because

Accepted Answer

A)   quasar fuzz produces stellar spectra.
B)   a few quasars have large red shifts.
C)   some quasars fluctuate rapidly.
D)   all of the above
E)   none of the above

Question 7

How are astronomers able to determine that quasars are so small?

Accepted Answer

A)   They are variable over a short period of time.
B)   They emit mainly X-rays.
C)   They are only found at very large distance.
D)   The structure of a quasar is completely resolved in images.

Question 8

Head-tail galaxies are

Accepted Answer

A)   found most often in clusters.
B)   dependent on an inter-galactic medium.
C)   powered by jets in the nucleus of the galaxy.
D)   a and b
E)   a,b,and c E

Question 9

Astronomers who discovered quasars found that they show ________ of their spectral lines and are thus probably much ________ than nearby galaxies.

Accepted Answer

A)   large red shifts,farther away
B)   large blue shifts,farther away
C)   no wavelength difference,nearer
D)   large red shifts,nearer
E)   large blue shift,nearer

Question 10

The disks which have been observed in the centers of some active galaxies evidently have a ____ at their centers.

Accepted Answer

A)   black hole
B)   main sequence star
C)   terrestrial planet
D)   jovian planet

Question 11

In the unified model of active galactic nuclei,the broad line region in an active galactic nucleus is

Accepted Answer

A)   composed of clouds of gas and stars moving at very high orbital velocities.
B)   composed of a super massive black hole.
C)   responsible for producing the bright continuous radiation observed in blazars.
D)   responsible for the narrow absorption lines seen in Type 2 Seyfert galaxies.
E)   located further from the core than the narrow line emission region.

Question 12

If a quasar has a red shift of 0.98,then it is receding from the earth at 98 percent the speed of light.

Accepted Answer

A) True 
 B)False

Question 13

How does the study of quasars reveal information of the history of the universe?

Accepted Answer

A)   Quasars are very distant so we can view how galaxy evolution occurred in the past.
B)   Quasars contain of stars of all ages.
C)   Quasars typically act as host galaxies for gravitational lensing.
D)   Quasars have been found to exist in every stage of the universe's evolution.

Question 14

Some quasars have fuzz around them that produces spectra like that of normal galaxies.

Accepted Answer

A) True 
 B)False

Question 15

Radio lobes are held together by their magnetic fields.

Accepted Answer

A) True 
 B)False

Question 16

Head-tail galaxies are pairs of galaxies interacting with each other.

Accepted Answer

A) True 
 B)False

Question 17

Double-lobed radio galaxies appear to be emitting jets of gas and radiation.

Accepted Answer

A) True 
 B)False

Question 18

Why do astronomers believe black holes are the source of an AGN's energy?

Accepted Answer

A)   It's expected since black holes have been found at the center of most galaxies.
B)   Radio jets are seen in many AGN and those only come from black holes.
C)   Black holes have been observed directly there.
D)   Only black holes can produce so much energy in such a small place.

Question 19

Most galaxies appear to be ...

Accepted Answer

A)   composed of one star and seven planets.
B)   inside our Milky Way.
C)   located on the Earth.
D)   moving toward us.
E)   moving away from us. E

Question 20

Encounters between galaxies would be ____ in the past versus now.

Accepted Answer

A)   the same
B)   more frequent
C)   less frequent

Exam 17: Active Galaxies and Supermassive Black Holes

The hydrogen Balmer line H β\betaβ has a wavelength of 486.1 nm in the laboratory.It is observed in a quasar at 2430.5 nm.What is the red shift of this quasar?

Correct AnswerverifiedD

The hot gas of a radio lobe could be held together by

Correct AnswerverifiedShow Answer

Astronomers can estimate the mass of the black hole at the center of the active galaxy M87 from the

Correct AnswerverifiedShow Answer

A(n) ____ is observed if our line of sight is parallel to the plane of the dense disk of an active galactic nucleus.

Correct AnswerverifiedShow Answer

Jet-shaped regions of radio and optical emission have been observed in

Correct AnswerverifiedShow Answer

We suspect that quasars are the active centers of galaxies because

Correct AnswerverifiedShow Answer

How are astronomers able to determine that quasars are so small?

Correct AnswerverifiedShow Answer

Head-tail galaxies are

Correct AnswerverifiedE

Astronomers who discovered quasars found that they show ________ of their spectral lines and are thus probably much ________ than nearby galaxies.

Correct AnswerverifiedShow Answer

The disks which have been observed in the centers of some active galaxies evidently have a ____ at their centers.

Correct AnswerverifiedShow Answer

In the unified model of active galactic nuclei,the broad line region in an active galactic nucleus is

Correct AnswerverifiedShow Answer

If a quasar has a red shift of 0.98,then it is receding from the earth at 98 percent the speed of light.

Correct AnswerverifiedShow Answer

How does the study of quasars reveal information of the history of the universe?

Correct AnswerverifiedShow Answer

Some quasars have fuzz around them that produces spectra like that of normal galaxies.

Correct AnswerverifiedShow Answer

Radio lobes are held together by their magnetic fields.

Correct AnswerverifiedShow Answer

Head-tail galaxies are pairs of galaxies interacting with each other.

Correct AnswerverifiedShow Answer

Double-lobed radio galaxies appear to be emitting jets of gas and radiation.

Correct AnswerverifiedShow Answer

Why do astronomers believe black holes are the source of an AGN's energy?

Correct AnswerverifiedShow Answer

Most galaxies appear to be ...

Correct AnswerverifiedE

Encounters between galaxies would be ____ in the past versus now.

Correct AnswerverifiedShow Answer

The hydrogen Balmer line H $\beta$ has a wavelength of 486.1 nm in the laboratory.It is observed in a quasar at 2430.5 nm.What is the red shift of this quasar?

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D

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E

Astronomers who discovered quasars found that they show of their spectral lines and are thus probably much than nearby galaxies.

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E

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