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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 thr2z bwvyrnvf 3d6gb08/a6 h,y:e;nhv e great range of brightness 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 scd2*30ip2mfxp 6:ia1rc gf h atars depends 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, 4usu;us- 83+cl s;vsdtk h t:eorange, red, and yellow. What is their rank from coolest to hottest 8:kuudls+3;hc-; te ss4 suvt?

Correct Answer:    
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Mark Problem
4#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  A Hertzsprung-Russell diagram 9z:hfcynjrn* *kd b+; shows stars on 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 toz;peys1x3 v 8-rqy z-hat of the Sun is 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 will colm da.6++uu0v g 5kfvtilapse into a white dwarf) is, if the masi5 +vv6ua +d g.tk0fums of 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 resulw/ we/cs(ri(s t in

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

Correct Answer:    
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Mark Problem
9#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Pulsars are rapidly spinnjmrdsj kgs) 7n24 +sw 1io.n7king

Correct Answer:    
Mark Problem
10#
 
Free-Response ( 1.0 marks) Whole-Paper View Save Problem  
State Einstein's principle of equiv2 vfr f hlp3xdu;q+9.falence.
Correct Answer:    
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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 cyu 4wcl 7*bf*wenter of a sphere within which not even light can escape. It was first discovered mathematically by Schwarzschild in 1916 after Eins 4*w7wfuy l*cbtein published his general relativity 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

Correct Answer:    
Mark Problem
12#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  When a distant source emits light of a particular wrzh9kd n a ty wb:cuvo cbo10u) 8a30,z*r0)bwavelength in the visible, and the source is moving away from uco dkb hnzauwc v ,twayrruo zb:) 01)90*083bs, the color of the light appears to us to be shifted toward the

Correct Answer:    
Mark Problem
13#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The cosmic background raoiiswzy 1c8iu(a8i mx+(s9 8udiation corresponds to a temperature of about

Correct Answer:    
Mark Problem
14#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Sun has apparent brightnessnrr ws dlw(n(c 13fd)9 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?

Correct Answer:    
Mark Problem
15#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  A star has absolute luminosity equal to that of tjq r kzwzb)47p9r5;brhe 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?

Correct Answer:    
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Mark Problem
16#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Earth's orbit has a mean radiusx)-y m hr+5gbl 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 a mean rff+j 87lnbhx o5 .d5qwadius 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 angle for Proxima Centauri, which is Earth's -+5 el5fskua:fbtwlbae9( )d nearest star at 4.3k+ef5lua (9t5 bfb-aes:)dl w ly?

Correct Answer:    
Mark Problem
19#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The apparent brightness.bcm; . ( c2g pjdthyeromx62a*la/8l of a star is $1.0 \times 10^{-12} \; W/m^{2}$ and the peak wavelength is 600 nm. Estimate its distance from us.

Correct Answer:    
Mark Problem
20#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  It can be shown that the approi eiu2g9q, qk97i3kal ximate age of the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, estimate the age of the universe, in yq7,2ag ukkl9 9eiqi3iears.

Correct Answer:    
Mark Problem
21#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  If a galaxy is moving away from ulr5x-0pr+v e:2n il vb*l 4wmms at 1.0% of the speed of light, how far away is it from um54lrbmx2r vvlp - i0lew* :+ns?

Correct Answer:    
Mark Problem
22#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Estimate the speed of a galaxy that is 10 bil/cae i9uqqb+f o ,yx5e: 9r7k-ch7vrmlion light-years away.

Correct Answer:    
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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 spectrum of a2gpm/)gz6tgfs4 3 km w star which is 100 million light-yea /tmk mfz )3s4ggw62gprs from us.

Correct Answer:    
Mark Problem
24#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  About 1 ms after the Big Bang, the temperature of the universe ; vzj 2 wt+ gimmrlw.suc+aup/6 rj8.,was about 1013 K. What energy (in eV) d;2 r.w, sc.mjtzuagu8 l w+/pi v6+jrmoes this correspond to?

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