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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 brightn*(12-g dct5ff ao+uxg (mf tyness 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 q p ,(r7jug/ht.w ob6efor most stars 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 cgdxx,gb.ahil0/ ./kq j(4 uvn mff27 blue, orange, red, and yellow. Wha. 7dlga/cx (,f/xu 0fkv hb.mn qjg4i2t 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 b-zu ap(ig6 i j*c(4bxnl+7m:qh3h coa 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 thgz ee yn:q3 q;06ugy3bat of the Sun is about the size of

Correct Answer:    
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Mark Problem
6#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Chandrasekhar limit of stellar mass (below5c-tn cr4pdz+ which a star will collapse into a white dwarf) is, i 4-cz+crnptd5f the mass 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 r5 uv 5*ind3xamzzi:6fesult 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:fdzlb;dgi5 prnksm5w.n3 v( xu ;0k9

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Mark Problem
10#
 
Free-Response ( 1.0 marks) Whole-Paper View Save Problem  
State Einstein's principle of euxnuy81 rt*fdv3 p,jvctm+.-quivalence.
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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 be*z( p((pclh(bwg3 t the center of a sphere within which not even light can escape. It was first discovered mathematicallytzlbw(pebc hpg*( (3 ( by Schwarzschild in 1916 after Einstein 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

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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 vicjg i3(0rdjb(,j zq,1q s.pcg sible, and the source(id. gg jqz0c (cj,3,bpq1rjs is moving away from us, the color of the light appears to us 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 t9 7bg:;ve1c6ft2epe 3q/ eop*r ghafzo a temperature of about

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Mark Problem
14#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Sun has apparent bri hal6sols7b1./ jazm9ghtness 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 equalx6a4mbcb k kp)y:c9f* 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 radius of 2 y yka06bdvk1$1.5 \times 10^{8} \; km$. 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?

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Mark Problem
17#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Earth's orbit has a mean -( urnhfv oxczngu0)l *p)z x*/ti*4u 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 angl8v p1jyzj:jl, e for Proxima Centauri, which is Earth's nearest star at:l8z,p1 vjjjy 4.3 ly?

Correct Answer:    
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Mark Problem
19#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The apparent brightness of j/*h(cpq gto 64t0f -t ee8d4+ef2j rwbdk6uia 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 qtm 90pzgfme7+ b, j0sapproximate 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 yez,gbm0 q9jes7 p+t0fmars.

Correct Answer:    
Mark Problem
21#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  If a galaxy is moving away from us at 1.0% of the speed of light,zar b/35 exf*z how far away is it fromfbzzx * 3r5ae/ 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 awayvw-syt7owo:m//;g6 *r ei iyx.

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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 a st) 1ogz331a whdax;vv tar which is 100 million li;3a1vo1)at xhwvzd3 gght-years from us.

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Mark Problem
24#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  About 1 ms after the Big Bang, the temperature of hg4lz5/i0 i(gjwiz9w 70blb j the universe was about 1013 K. What ljhb0ii 0iwlg bwj g(5/zz 479energy (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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