Question 1

An iron rod heated to 3,000 K will emit a(n)________ spectrum.

Accepted Answer

A)  continuous 
B)  emission line 
C)  absorption line 
D)  band

Question 2

A star moves rightward with a velocity of 100 m/s,as shown in the figure below.Observers stand at positions A,B,and C.Compared to reference wavelengths measured in the laboratory,how would each of these observers see the star's absorption lines shift?

Accepted Answer

The answer of A star moves rightward with a velocity...

Question 3

A rubber ball falls from a height of 1,000 m,accelerates,and then impacts Earth.During the impact,it heats up so much that it melts.The melted rubber glows and eventually cools off.How would you describe the flow of energy in this scenario?

Accepted Answer

The answer of A rubber ball falls from a height...

Question 4

The figure below shows a model of an atom.Which of the following electron transitions would release a photon with the most energy?

Accepted Answer

A)  2 to 1 
B)  4 to 1 
C)  1 to 2 
D)  1 to 4

Question 5

The Chandra X-Ray Observatory achieves high angular resolution with:

Accepted Answer

A)  interferometry. 
B)  a large diameter aperture. 
C)  grazing incidence mirrors. 
D)  lead plates that block unwanted X-rays.

Question 6

Consider the experiment shown in the figure below.Identify the spectra observed at spectrographs A and B,and explain how the Bohr model accounts for the features in these spectra.

Accepted Answer

The answer of Consider the experiment shown in the figure...

Question 7

An astronomer using a refracting telescope sees an image of two gas clouds with identical shapes but displaced slightly from each other.One is composed of blue light and the other red light.The most likely explanation is:

Accepted Answer

A)  the Doppler effect. 
B)  chromatic aberration. 
C)  dust absorption. 
D)  interstellar scattering.

Question 8

Type I supernovae all have (nearly)identical luminosities.Explain how this fact allows us to measure their distances.

Accepted Answer

The answer of Type I supernovae all have (nearly)identical luminosities.Explain...

Question 9

List the seven components of the electromagnetic spectrum from shortest to longest wavelength.

Accepted Answer

The answer of List the seven components of the electromagnetic...

Question 10

Among the following,which is the most important reason to make telescopes large?

Accepted Answer

A)  atmospheric seeing 
B)  chromatic aberration 
C)  magnification 
D)  light-collecting power

Question 11

If the wave shown in the figure below travels to the left with a speed of 8 m/s,what is its frequency?

Accepted Answer

A)  8 Hz 
B)  4 Hz 
C)  2 Hz 
D)  1 Hz

Question 12

An opaque cloud of dust at 10 K will emit:

Accepted Answer

A)  a continuous spectrum. 
B)  an emission line spectrum. 
C)  an absorption line spectrum. 
D)  no light.

Question 13

A telescope can barely detect a star situated at 1 kpc from Earth.If an identical star were placed 4 kpc from Earth,how much larger would the radius of the telescope have to be to observe it?

Accepted Answer

The answer of A telescope can barely detect a star...

Question 14

Which of the following sites would make the best location for an infrared telescope?

Accepted Answer

A)  the South Pole 
B)  a deep valley 
C)  an arctic mountain 
D)  a high-altitude desert

Question 15

What is the wavelength of the wave shown in the figure below?

Accepted Answer

A)  8 m 
B)  4 m 
C)  2 m 
D)  1 m

Question 16

A telescope with a diameter of 2 m is just barely able to resolve features on a gas cloud when observing it at 500 nm wavelength.Which of the following observations would also just barely be able to resolve these features?

Accepted Answer

A)  a 1-m diameter telescope observing at 1,000 nm 
B)  a 4-m diameter telescope observing at 125 nm 
C)  a 4-m diameter telescope observing at 250 nm 
D)  a 1-m diameter telescope observing at 250 nm

Question 17

An astronomer measures the luminosities of two stars with identical sizes,finding that star A is 256 times as luminous as star B.How are their temperatures related to each other?

Accepted Answer

A)  Star A is twice as hot as star B. 
B)  Star A is 4 times hotter than star B. 
C)  Star A is 16 times hotter than star B. 
D)  Star A is 64 times hotter than star B.

Question 18

Stars A and B have identical luminosities,but star A is twice as far away as star B.How does the brightness of these two stars compare?

Accepted Answer

A)  Star A is two times brighter than star B. 
B)  Star A is four times brighter than star B. 
C)  Star A is two times fainter than star B. 
D)  Star A is four times fainter than star B.

Question 19

Which of the following varieties of light has the LOWEST frequency?

Accepted Answer

A)  green 
B)  yellow 
C)  blue 
D)  red

Question 20

A spectrum of an unknown material reveals discrete bright lines with long,dark gaps between them.Which of the following could describe the unknown material?

Accepted Answer

A)  a hot cooking pot 
B)  cool chicken noodle soup 
C)  steam 
D)  ice made opaque by high pressures

Exam 4: A Universe of Universal Laws

An iron rod heated to 3,000 K will emit a(n) ________ spectrum.