Please select To the mobile version | Continue to access the desktop computer version

WebAssign

 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.


习题练习:Physics Unit33: Astrophysics and Cosmology  作者: physics

答题人: 匿名未登录  开始时间: 23年05月02日 09:42  切换到: 整卷模式

标记此题
1#
 
单选题搜藏此题  
  The appearance of the greym7vjo g 9.yn) 8zuuije; s:8bat range of brightness among stars is due to (1.0 分)
参考答案:    
标记此题
2#
 
单选题搜藏此题  
  The absolute luminosity for most stars4a l6 - jv5rnp5kxian6e:ib.h depends on the (1.0 分)
参考答案:    
标记此题
3#
 
单选题搜藏此题  
  Four different main-sequence stars are colored blxn(c+kszx ,, que, orange, red, and yellow. What szc,+ n,(xqkx is their rank from coolest to hottest? (1.0 分)
参考答案:    
标记此题
4#
 
单选题搜藏此题  
  A Hertzsprung-Russell diagdrd.di+;bvm; x3ey;c ram shows stars on a plot of (1.0 分)
参考答案:    
标记此题
5#
 
单选题搜藏此题  
  A white dwarf star with a mass e;mc4 dr3kd ik9cxsu51 qual to that of the Sun is about the size of (1.0 分)
参考答案:    
标记此题
6#
 
单选题搜藏此题  
  The Chandrasekhar limit of stellar mass (below which :ox q*ermj;8(oh uqtp0oj 6u/a star will collapse into a whitp :/u hoteoj(xoqu*m068 r;qje dwarf) is, if the mass of our Sun is M, about (1.0 分)
参考答案:    
标记此题
7#
 
单选题搜藏此题  
  Supernovas are thought to always resunic ,p.j.qg /rlt in (1.0 分)
参考答案:    
标记此题
8#
 
单选题搜藏此题  
  Black holes (1.0 分)
参考答案:    
标记此题
9#
 
单选题搜藏此题  
  Pulsars are rapidly spinnizp 57x2/+3 bfp .sr*zcjsa:swmy 7xmn ng (1.0 分)
参考答案:    
标记此题
10#
 
问答题搜藏此题  
  State Einstein's principle of equivaley,mm3 yqpo8*tn7te0r 1+fx xpnce. (1.0 分)
参考答案:    
标记此题
11#
 
单选题搜藏此题  
  The Schwarzschild radius of a black hole is that radial osj ,wb6 i9d7pj,lm hgt/d:l(distance from the center of a sphere within w/ 96( 7bglsjtjmo dih,,pd:wlhich 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 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 (1.0 分)
参考答案:    
标记此题
12#
 
单选题搜藏此题  
  When a distant sourcei 0x3m.z-zywn emits light of a particular wavelength in the visible, and the source is movin-z wizx0 mny.3g away from us, the color of the light appears to us to be shifted toward the (1.0 分)
参考答案:    
标记此题
13#
 
单选题搜藏此题  
  The cosmic background radiation corresponds to a temperature of aboutbdu) k11d *3p vtyolv1 (1.0 分)
参考答案:    
标记此题
14#
 
单选题搜藏此题  
  The Sun has apparent brightnen v-mlj5lye qw/4o .xw2b7-xr ss 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? (1.0 分)
参考答案:    
标记此题
15#
 
单选题搜藏此题  
  A star has absolute luminosity equal toh.u cv:5.l*zw sugr/s 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? (1.0 分)
参考答案:    
标记此题
16#
 
单选题搜藏此题  
  The Earth's orbit has a mean radius of k1p *fpv- u/zu$1.5 \times 10^{8} \; km$. 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? (1.0 分)
参考答案:    
标记此题
17#
 
单选题搜藏此题  
  The Earth's orbit has a mean 28,mp tqlaqeka j4+8xradius 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 = $9.46 \times 10^{15} \; m$) (1.0 分)
参考答案:    
标记此题
18#
 
单选题搜藏此题  
  What is the parallax angle for Proxima ,x,i 2 y*) 5yvpn1zt.lfq dejmCentauri, which is Earth's nearest star atflje,p2zyni d) 5tqx,vm y*.1 4.3 ly? (1.0 分)
参考答案:    
标记此题
19#
 
单选题搜藏此题  
  The apparent brightn1kfz8h78zzhh p.svh , ess of a star is $1.0 \times 10^{-12} \; W/m^{2}$ and the peak wavelength is 600 nm. Estimate its distance from us. (1.0 分)
参考答案:    
标记此题
20#
 
单选题搜藏此题  
  It can be shown that the++i dvewih; bqk3v yhmq6-.1 l approximate age of the universe is 1/H, where H is the Hubbl vkmqw +31;q +vh6ehy bid-il.e constant. Taking H = 20 km/s/Mly, estimate the age of the universe, in years. (1.0 分)
参考答案:    
标记此题
21#
 
单选题搜藏此题  
  If a galaxy is moving awau7cqm2 ,;g9kzd b nk0ny from us at 1.0% of the speed of light, how far away is it frbcmz n9uq27dn ;0 kg,kom us? (1.0 分)
参考答案:    
标记此题
22#
 
单选题搜藏此题  
  Estimate the speed of a galaxy that is 10 billion light-yea6(- l- r7 jftzyfwpxs1rs away. (1.0 分)
参考答案:    
标记此题
23#
 
单选题搜藏此题  
  Estimate the observed wavelength for the 656 nm line in the spectrfw coj01n-f bcto0k2 zp :3hzbzb2q* rp7z)k:um of a star which is 100 rhb:0zb- ok)z1cn3 2ztk*2po7: bz qfcp fjw0million light-years from us. (1.0 分)
参考答案:    
标记此题
24#
 
单选题搜藏此题  
  About 1 ms after the Bi88 xds,j5t0xh8z( u(ynfrb f6tzi6cs g Bang, the temperature of the universe was about 1013 K. What energy (in eV) does this corres65bz(8hi (jsd8f y xtx,usrfn6tz 80c pond to? (1.0 分)
参考答案:    
  • 答题人:
  • 总分:24分 及格:14.4分 时间:不限时
    未答题: 已答题:0 答错题:
    当前Practice共有 24 道题

    Archiver|手机版|Jailroom|WebAssign

    2024-5-27 19:48 GMT+8 , Processed in 0.097448 second(s), 60 queries , Redis On.