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PRACTICE：Physics Unit33: Astrophysics and Cosmology
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 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 brightnwm8 1vgdq36b;tvvc/ o ess 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 depends on c3qgno;q:x d:xu7w6p;jq2qcpi da5 / the

Correct Answer:    
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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, orange, red, w3l6 vhyqaz6io,5y6n and yellow. What is their rank from coolest to hzlnoai5 y6qh 6w6,v3 yottest?

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Mark Problem
4#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  A Hertzsprung-Russell diagj ec:7p)ebu f-*jtmx4 +x)-gu 1onxdtram 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 that of the Sun is about the s+ qlzo3vd9 su r0 ry*eg6gn*e ts/8jp/ize of

Correct Answer:    
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Mark Problem
6#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Chandrasekhar limit of stes qw 3p;1-kxci5mg)ojz6 3 puhllar mass (below which a star will collapse into a white d 3ckzoqw3u ig;-ppj5xs)6 mh1warf) is, if 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 jcix-i05v7)7gf1m54sfbwld3 r ax xk to always result in

Correct Answer:    
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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 kpq h*dbrelu 5r5yog)z4(q9 2

Correct Answer:    
Mark Problem
10#
 
Free-Response ( 1.0 marks) Whole-Paper View Save Problem  
State Einstein's principle of equivalelbj8 ),abh;me0 -y:0kyju4t 9r s6cwvc nzz0qnce.
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 distan i3lu7d0g xe9kce from the center of a sphere within which not even light cx0 d73i9eg lkuan 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:    
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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 y/k6oid6kw 3p visible, and the source is63po yk6wi /kd 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 radiation corres91 xvi4xq dbj(aj;ejp8gq*i+ ponds to a temperature of about

Correct Answer:    
Mark Problem
14#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Sun has apparent brightness a r.yhliwie v;4w,+9 njt 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 luminoshd tl:tfpg-b q fbx.w 2.+n4yv(1 f0mvity equal 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:    
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Mark Problem
16#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Earth's orbit has z*i0.*6b .f 7xoo+hygv lato/emf8 eua 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 km?

Correct Answer:    
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Mark Problem
17#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The Earth's orbit has a mean radi/u(9rh x2qonqy,1bk vajm )fy3v ;+u tus 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 f upf-mr+f mviq14q-yywt5d* m4rr 5m: or Proxima Centauri, which is Earth's nearest star aty-*f5 w4t 4 r1d: mmvim uqyqrr5-pmf+ 4.3 ly?

Correct Answer:    
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Mark Problem
19#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  The apparent brightn5 9mh9e vvw2deess 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 approximate age vxp5 klklw,paf/0);b8, ry s-buk7nfu3e c6 cof the universe is 1/H, where H is the Hubble constant. Taking H = 20 p)/;wfb nx3 ay0svcu,7,lr58b-kcfp6 kkule km/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 ofv6tl 0 ;gbukx0o5uwdmbb,8/i light, how far away is it f/w8oim5,utu blx 6 0v0gbd;bkrom us?

Correct Answer:    
Mark Problem
22#
 
Single-Choice ( 1.0 marks) Whole-Paper View Save Problem  
  Estimate the speed of a galaxy that qax j7)uh2m: ;h-nmt6ao/ :mb1jnpasis 10 billion 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 z6s8;m jjm3jl for the 656 nm line in the spectrum of a star whicmj3 s 68zjmlj;h is 100 million light-years 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 was about jvoe +x.07mgz1013 K. What energy (in eV) does this correspond +ogxjv0z7m.e to?

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