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PRACTICE：Physics Unit33: Astrophysics and Cosmology
本Practice来源于https://webassign.org，是在线Practice的打印版，您也可以访问本平台网站(https://webassign.org/)直接在线完成(注册并登录账号后在首页左侧输入试卷号 332 即可在线作答)，，作答电子化后可随时回放，查看每题答案与详细解析，搜藏保存任意题目；教师使用本平台可以抽题组卷或一键复制他人试卷，布置为在线考试或在线作业，全自动判分成绩一键排序导出，省时省力。本试卷的直接作答链接 https://webassign.org/test332.html
 Author: physics    Total Marks: 24 mks  Marks Awarded: _____________

User Name: No Login  Start Time: 23年05月02日 09:42  Switch to Whole-Paper Mode

Mark Problem
1#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The appearance of the great range of bright)is4 ydl d 3;5te /zdpw)wd7nnness among stars is due to

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Mark Problem
2#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The absolute luminosity for most stars depends d h ,ado)*ggd(1/xvpd on the

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Mark Problem
3#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Four different main-sequence stars are colored blue, orange, red, and dad-cu2 u56u ru6f)shyellow. W sdru5u6h c-udfa2u )6hat is their rank from coolest to hottest?

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Mark Problem
4#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  A Hertzsprung-Russell diagram shows stars on ycx8gg05 (wylq)/5 : n y-njehlwxmm7 a plot of

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Mark Problem
5#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  A white dwarf star with a mass equal to that of the Sun is fhnmgdzy0p qayi;i.k8)h zmc-0+ . 0i about the size of

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Mark Problem
6#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Chandrasekhar limit of stellar mass (below which a star wilehsy xs, .ru2erp4vm(c xo. . 1ch0zj*l collapse into a white dwarf) is, if the mass oes.u j40(oyc r. *r,cxhp2.v1exzs hm f our Sun is M, about

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Mark Problem
7#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Supernovas are thought to always resulb o w84,a3-tmz- mvodlt in

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Mark Problem
8#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Black holes

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Mark Problem
9#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Pulsars are rapidly spinning.; +n++c :k ckdvfhcrce9 8khz

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Mark Problem
10#
 
Free-Response ( 1.0 marks) Whole-Paper View Save Problem  
State Einstein's principle of equi:,px i 4x; 4c,vzy*mqsjiur.ivalence.
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Mark Problem
11#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Schwarzschild radius of a black hole is that radial distance from the cen/l*mt s/ h*rskter of a sphere within which not even light can escape. It was first discovered mathematically by Schwarzschild in 1916 after Einstein published his general retm*k r/h*lss/ lativity theory. It can be calculated from a star's mass M as: $R = 2GM/c^2$. Take the radius of both stars A and B as the Schwarzschild radius. If the mass of star A is twice as much as the mass of star B, the average density of star A, compared to star B will be

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Mark Problem
12#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  When a distant source emits light of a particular wavelength in the visible, 1suzpie moaa3u :3 osw,z*)h.and the source is moving away from us, the color of the light appears to us 3eowpiu )1u3 ash ,moazz*:.s to be shifted toward the

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Mark Problem
13#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The cosmic background radiation corresponds to a temperature cn(/7y6y xgczof about

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Mark Problem
14#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Sun has apparent brigdxn( ;q4:skhs +:v8vj16f t ie lsjb,6ilcy1vhtness at Earth ($1.5 \times 10^{8} \; km$ away) of B. What would be the apparent brightness of the Sun at Pluto, which is $6.0 \times 10^{9} \; km$ from the Sun?

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Mark Problem
15#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  A star has absolute luminos;m 53 zxaaa* ljawe y4yb2c(1dity equal to that of the Sun ($1.5 \times 10^{8} \; km$ from the Earth) but is 10 pc away from the Earth. By what factor will it appear dimmer than the Sun?

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Mark Problem
16#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Earth's orbit has a mean rao9uxko* t;-ue dius of $1.5 \times 10^{8} \; km$. Over a six-month period, the apparent position of a particular star varies by $0.00014^{\circ}$ due to parallax. How distant is the star, in km?

Correct Answer:    
Mark Problem
17#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Earth's orbit has g rtb:p2t0pngi0 z h/h:w x)o)a mean radius of $1.5 \times 10^{8} \; km$. Over a six-month period, the apparent position of a particular star varies by $0.00014^{\circ}$ due to parallax. How distant is the star, in ly? (1 ly = $9.46 \times 10^{15} \; m$)

Correct Answer:    
Mark Problem
18#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  What is the parallax x/ez 2z.(p bf 0kssve.angle for Proxima Centauri, which is Earth's nearest star at 4.3 ly?ezx/ .eszb0k(v2fsp .

Correct Answer:    
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Mark Problem
19#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The apparent brightness of r54it4fp + wiwa star is $1.0 \times 10^{-12} \; W/m^{2}$ and the peak wavelength is 600 nm. Estimate its distance from us.

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Mark Problem
20#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  It can be shown that the approximate age of the universe is 1/H, w; fdod)2vbt( ./lsnughere H is the Hubble constant. Taki2;gtsln/dd ( )ovubf.ng H = 20 km/s/Mly, estimate the age of the universe, in years.

Correct Answer:    
Mark Problem
21#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  If a galaxy is moving away from o*y9rxegj 65)ip oj+qus at 1.0% of the speed of light, how far away is it from+6eo 9p5yxjj r *ogqi) us?

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Mark Problem
22#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Estimate the speed of a galaxy that is 10 billion light-years awa 5tvk8fj pwv-e.nlv5q peeaap 0 sj:a4)z0/5dy.

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Mark Problem
23#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Estimate the observed wavelength for the 656 nm line in the qwr:h5ulc8af 8e 5yak:r s -m,apb i;,spectrum of a star which is 100 million light-ye:58pq,s 8eahy ra,cbwf-m;: lak iu5rars from us.

Correct Answer:    
Mark Problem
24#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  About 1 ms after the Big Bang,1 e(ty0gnb pc* the temperature of the universe was about 1013 K. tcypbg*0( n1eWhat energy (in eV) does this correspond to?

Correct Answer:    
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    Total:24 mks Pass:14.4 mks Duration:Unlimited
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