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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 gr;pyrc2iw s1 a bk 2i/v2taouhg*2zy: 8eat 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 stars depetd*oo -/ ytqxh) h/nqg1b9 c*wnds on the

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Mark Problem
3#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Four different main-sequence q0xxscx*hh+my;r1 gr2eo(u: g9+h xystars are colored blue, orange, red, and yellow. What is their rank fr( h19hyxr ucgr+*mhe 2qx: 0;+yxgsxoom 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 dy/4a(ucf sk5 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 acnj:43 cq/x ivokt6v 9 mass equal to that 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 whicye(e)ajv /z (toblv ct5f9w/:h a star will collapse into a white dwarf) is, if the mass of our Sunya9w bvevo(/l(e: 5ft)tcj / z 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 resu8jvlq/;chnvc x) 3wmc;)d dt;lt in

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

Correct Answer:    
Mark Problem
9#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Pulsars are rapidly ;j t:wz r2d(prspinning

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Mark Problem
10#
 
Free-Response ( 1.0 marks) Whole-Paper View Save Problem  
State Einstein's principle 3t edk-k,icfpilf+37 ms7(jq7oy s:w of equivalence.
Correct Answer:    

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 tjw azxhsu;mgth (5q - 6bf+d;8he center of a sphere within which not even light can escape. It was first discovered mathematically by Schwarzschild in 1916 after Einstein published his general relativity theory. It can be calculated from a star's masszhfbs5w8x6 d;qjh+- (aut m;g 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 wavelengthd6 uunp70*jy x in the visible, and the source iuun*j706 y dxps moving away from us, 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 radiat*va 41y)m vv x/ywa/i fjl494diwwl9 gion corresponds to 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 brightness eez: t2 dntz0zdj ssw)4yd58(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 equaq krr d8buwu m)*+3rpz-d z59ql 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?

Correct Answer:    
Mark Problem
16#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Earth's orbit has a msahbyb ukg lek, l3: (+swt-6jrb9f )6ean 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 km?

Correct Answer:    
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Mark Problem
17#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Earth's orbit haqyyoppmm )-h,z;(ar h zo,+4 gs 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 angle fo;,n1)* tsv69i mu7u ybt ch4ra dg-iyvr Proxima Centauri, which is Earth's nearest star at 4.3 ly?4sh c1vt)a- gdu 7ny6uitm y9i v;,*rb

Correct Answer:    
Mark Problem
19#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The apparent brightness of 4+ )yugj11qw:ip f knga 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 approximate age of the universe is 1/H, where H isete/*0lm4oeoo/qz o*5 f:elo pe ,cv+ the Hubble constant. Taking H = 20 km/s/Mly, estimate the age o/olt,o4 eme *o0eep+ql/ o5v o:*fczef 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 uku05 cn1th3p jg8 *1jotot: zrs at 1.0% of the speed of light, how far away is it from uugnh:tjo8jot3k* pzc 0511rts?

Correct Answer:    
Mark Problem
22#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Estimate the speed of a galaxy that is 10 billion light-y qum/08br,-2tb 77vt wbagigw s6lt3qears 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 imzc37 llds3,x n the spectrum of a star which is 100 million light-years fx ,37dl c3lmszrom us.

Correct Answer:    
Mark Problem
24#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  About 1 ms after the Big Bang,1)iw ,qsecdw0x 3i p2 kocdx:- the temperature of the universe was about 1013 K. What energy (in eV) does thisdi-xx ki,1:cwe0)o3cds 2wp q correspond to?

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