Physics Unit33: Astrophysics and Cosmology

1#

The appearance of the great range of brightness amofoplb(:7ls *: y pde,e+mqo/qng stars is due to

A. the differences in the amount of light different stars emit.

B. the differences in the distances of stars from us.

C. both of the given answers

D. none of the given answers

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2#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The absolute luminosity for most stars depenb /p9z mjpo*i0ds on the

A. radius of the star.

B. cross sectional area covered by the star.

C. volume covered by the star.

D. the mass of the star.

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3#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Four different main-sequence stars are colored blue, orange, red, and yellowlhijyva)u/ f5+xc r2yr/z+s9a l)ck: . What is their rank from coolest to hottest?z2k:+ca usi h5 r9v/rl)+lyya/)c fx j

A. blue, yellow, orange, red

B. orange, blue, yellow, red

C. red, orange, yellow, blue

D. red, yellow, orange, blue

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4#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A Hertzsprung-Russell diagram shows stars on 1iwxmf3f a3zpaqv-ms x9 *f/ 7a plot of

A. apparent brightness vs. temperature.

B. luminosity vs. temperature.

C. luminosity vs. distance.

D. magnitude vs. apparent brightness.

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5#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A white dwarf star with a mass equal to that of the Suum ay 8(-emqd0n is about the size of

A. the Sun.

B. the Earth.

C. a basketball.

D. a baseball.

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6#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The Chandrasekhar limit of stellar mass (below which a star will c1h/a3x-ca.ihce)maf ollapse into a white dwarf) is, if the mass of our Sun is M, a a1)h/.-xc3c fhemaiabout

A. 0.8 M.

B. 1.2 M.

C. 1.4 M.

D. 1.9 M.

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7#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Supernovas are thought l+8fx h2jiq 7ana)gevr*9ra4 to always result in

A. neutron stars.

B. red giant stars.

C. regular stars like our Sun.

D. white dwarfs.

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8#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Black holes

A. are holes in space, devoid of matter.

B. are predicted by Einstein's special theory of relativity.

C. are the collapsed remnant of stars.

D. cannot be detected in binary star systems.

E. are a violation of Einstein's general theory of relativity.

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9#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Pulsars are rapidly spiwok4 1wj.ewb 3kzzyn)j(ci*w, r8d6cnning

A. regular stars like our Sun.

B. red giant stars.

C. neutron stars.

D. white dwarfs.

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10#

问答题 ( 1.0 分) 切至整卷模式搜藏此题

State Einstein's principle of equivalence. z0h17rjuw-i 4y cip13yw5f*lbf ,zvo

该题自我估分: (必填) (满分:1.0分)

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11#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The Schwarzschild radius of a black hole is that radial distanjxr*b c, )*mzice from the center of a sphere within which not even light can escape. It was first discovered mathematically by Schwarzschild in 1916 azc jmrxi*),b* fter 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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12#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

When a distant source emits light of a particular wavelength in the visioyt9cq-8(*6klea ht f 1bu;48a )sqxx(rp xjfble, and the source is moving away from us, the color of the light appears to us to be s*(4h xxfet 86qax kb9 olsa u8yrf-)1(;jqtpchifted toward the

A. red end of the visible spectrum.

B. blue end of the visible spectrum.

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13#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The cosmic background rawjo,, p dwwt.xe6k/) ldiation corresponds to a temperature of about

A. 1.4 K.

B. 2.7 K.

C. 3.0 K.

D. 3.3 K.

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14#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The Sun has apparent brightness at E s+co/1ru9c war wxgs3,kb- :garth ($1.5 \times 10^{8} \; km$ 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?

A. $0.25 \; B$

B. $0.063 \; B$

C. $0.025 \; B$

D. $0.00063 \; B$

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15#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

A star has absolute luminosity equal : dwrka ,,aduw-el(g4to 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?

A. $2 \times 10^{-9}$

B. $2 \times 10^{-11}$

C. $2 \times 10^{-13}$

D. $2 \times 10^{-15}$

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16#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The Earth's orbit has o9.qs):ndn,g +zr, yop4t rupa 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?

A. $1.2 \times 10^{11} \; km$

B. $1.2 \times 10^{14} \; km$

C. $1.2 \times 10^{17} \; km$

D. $1.2 \times 10^{20} \; km$

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17#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The Earth's orbit has a meanf6 ,xdty- gh:y 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 = $9.46 \times 10^{15} \; m$)

A. $0.13 \; ly$

B. $1.3 \; ly$

C. $13 \; ly$

D. $130 \; ly$

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18#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

What is the parallax angle for Proxima Centauri, whin: 6/- g4vo fsbwxgzjmy 94b0wch is Earth's nearest star at v:94b-zwgm0wn/j 6 yfs4g xob4.3 ly?

A. $1.2 \times 10^{-14} \; degrees$

B. $2.1 \times 10^{-4} \; degrees$

C. $1.2 \times 10^{-7} \; degrees$

D. $2.1 \times 10^{-7} \; degrees$

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19#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

The apparent brightness of a sp4. bte64emay tar is $1.0 \times 10^{-12} \; W/m^{2}$ and the peak wavelength is 600 nm. Estimate its distance from us.

A. $0.90 \; pc$

B. $9.0 \; pc$

C. $90 \; pc$

D. $900 \; pc$

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20#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

It can be shown that the appro*xw psi 2ray1iyh4p*x2sga09ximate age of the universe is 1/H, where H is the Hubble constant. Taking H = 20 km/s/Mly, *19saypi2xpx *r0 siy42hagwestimate the age of the universe, in years.

A. 15 thousand years

B. 15 million years

C. 15 billion years

D. 15 trillion years

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21#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

If a galaxy is moving awayj kntzm:lk68j.i* d o+ib t x*tf6v7u. from us at 1.0% of the speed of light, how far away is it fr* ltbkfdj u.67+ ik86zj inxom.tv *t:om us?

A. 200 ly

B. 200 thousand ly

C. 200 million ly

D. 200 billion ly

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22#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Estimate the speed ofj8:6xju r)pvsl48 uxvusbzr. / x(ej/ a galaxy that is 10 billion light-years away.

A. $0.1 \; c$

B. $0.3 \; c$

C. $0.5 \; c$

D. $0.7 \; c$

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23#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

Estimate the observed wavelength for the 656 nm line j+iv mhl12x+q in the spectrum of a star whi1vihmxl+q2+ jch is 100 million light-years from us.

A. $653 \; nm$

B. $656 \; nm$

C. $659 \; nm$

D. $692 \; nm$

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24#

单选题 ( 1.0 分) 切至整卷模式搜藏此题

About 1 ms after the Big Bang, the temperature of the u:ovrz6yz w7r 6 fhx+jgwv/- js fo-9/kniverse was about 1013 K. What energy (in eV) does this corresoz wjrvy sf/ r-f o9z-7jgvx6w:+ h6/kpond to?

A. $1 \; keV$

B. $1 \; MeV$

C. $1 \; GeV$

D. $1 \; TeV$

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