https://webassign.org

 Forgot password?
 Register Now

 

      

Upload Images

Unused Images

Tips: allowed image types are: gif, jpg, jpeg, png, webp; When uploading is finished, thumbnails will be generated and shown above. You can either double click on the thumbnail or simply drag the thumbnail with your mouse, the image will be bound to the current problem and displayed below it.

Used Images in Current Log

Tips: What is shown in this column are all the images associated with this exam log. Those bound to a particular problem will also be displayed immediately underneath it; Deleting any images will make them to be transfered to the "Unused images" category.


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 zuzi);+ji5(s5ozv q yess among stars is due to

Correct Answer:    
本Practice全部题目来源于https://webassign.org，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师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
Mark Problem
2#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The absolute luminosity for most 5k2 mrxb;75e xqry/ pbstars depends on the

Correct Answer:    
Mark Problem
3#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Four different main-sequence stdn)zxv8 x(*;)bk0mjwx3f lv cars are colored blue, orange, red, and yellow. What is their ran)*bwz3;x)n vvmk jlx0dc (8 xfk from coolest to hottest?

Correct Answer:    
Mark Problem
4#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  A Hertzsprung-Russell diagram shows stars on a plot ofq(z1eie ) ocog4+cv lr+fh n*+

Correct Answer:    
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 abc;k 0cbks f-ovob- *v1out the size of

Correct Answer:    
Mark Problem
6#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Chandrasekhar limit of stellar mass (below which a ()wpkj d+3kvfn sy(s, /d5fva r *d7mcstar will collapse into a white dwarf) is, if the mass of ourpywkf+a)s n5md( fsv* 3, vk/(dd7 rjc Sun is M, about

Correct Answer:    
本Practice全部题目来源于https://webassign.org，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师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
Mark Problem
7#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Supernovas are thought to(fv3ldtz6q/ 7x awi e( always result in

Correct Answer:    
本Practice全部题目来源于https://webassign.org，学生可自助刷题练习，扫右侧二维码加微信，获取学习资料，答疑辅导
教师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
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 spiz vd f z3v,gy2r,6,utznning

Correct Answer:    
Mark Problem
10#
 
Free-Response ( 1.0 marks) Whole-Paper View Save Problem  
State Einstein's principle o:psf18o7p / z);chy jvbqli-of equivalence.
Correct Answer:    

Mark Problem
11#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Schwarzschild radius of a black h nepp ;c/3j7bvsb b5o(ole is that radial distance from the center of a sphere within which nvc/7 ;s(oe bbj5p3b pnot 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 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 part(it4m tp qd x/u7eu2i0icular wavelength in the visible, and the source is moving away from us, the color of the light appears to us to be shifted tpeq( /di2 m7itx0tuu4oward the

Correct Answer:    
Mark Problem
13#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The cosmic background radiation corresponds to a0ixm (n ahzp0l1x0cs3 temperature of about

Correct Answer:    
Mark Problem
14#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Sun has apparent brightn/cqd0og0s 3 6,tkinut ess 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 t::ixd )m:j zmd30vot xhat 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 mapxwb-+9*u .lsjcp, hean 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:    
Mark Problem
17#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Earth's orbit has a mean radiupgz )* oeo j2faxz7ftoth/6d9+a.ds4 s 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 forr w;u83 mhp)zs Proxima Centauri, which is Earth's nearest star at 4.3 pzr;hus m )w38ly?

Correct Answer:    
Mark Problem
19#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The apparent brightness oy;dlnha(92i zm plyb5 uf6,k pr k.91yf 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 hhfimz)gxdw ;+,a t+, the approximate age of the universe is 1/H, where H is the Hubble constant. Taking H = 20 kmwhi;hm x f+,gtz d,+)a/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 us at 1.0% of the speed of light, how far away j c-fy i-57ax 4zcilsh(o 9hu0i icohc9i-a(-4hxzlyf 7 s5j0us it from us?

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-yearhy;(44 b:rqwex,i rrv s away.

Correct Answer:    
Mark Problem
23#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Estimate the observed wavelength for the 656 nm line -08c/ ixzm uq5t6dx+pdk/,w nu9tbq k in the spectrum of a star which is 100 million light-years fr+bkxp n 86u,59wiud t/z k-tm 0d/qqxcom 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 tzdja4 9+y8x k 7ptyeh-n1h3auhe universe was about 1013 K.793z-8 e+nh1 dpha4 yaxkjy ut What energy (in eV) does this correspond to?

Correct Answer:    
  • :
    •
    Total:24 mks Pass:14.4 mks Duration:Unlimited
    未答题: 已答题:0 答错题:
    当前第 题，此次Practice共有 24 道题

    试卷内容到此结束!   © 2024 https://webassign.org版权所有

    Archiver|Mobile Version|Jailroom|https://webassign.org

    2024-12-27 09:29 GMT+8 , Processed in 0.093187 second(s), 60 queries , Redis On.