E1 Astronomy and Space ScienceChapter 1 The Universe as Seen in Different Scales
1The Universe as Seen in Different Scales
New Senior Secondary Physics at Work1 Oxford University Press 2011
E1 Astronomy and Space ScienceChapter 1 The Universe as Seen in Different Scales
Practice 1.1 (p. 11)
1B
2D
1.23 rad == 70.5
B: 7047 = = 70.8 1.23 rad
3B
0.292 pc = (0.292 3.26) ly = 0.95 ly
4A
5V, II, IV, I, VII, VI, III
60.7 AU = (0.7 1.50 1011) m
= 1.05 1011 m
71.52 AU = (1.52 1.50 1011) m
= 2.28 1011 m
Time required =
= 760 s
= 12 min 40 s
875 000 years
9Number of galaxies laid edge to edge
=
= 27
It would take 27 galaxies like our own laid edge to edge to reach Andromeda.
10It reflects the light from the Sun to the Earth.
11(a)5 million
(b)5
(c)5 billion
(d)15 billion
12(a)(i)Distance moved in 1 day
= 2 (1.50 1011)
= 2.582 109 m
= 2.58 109 m
(ii)Distance moved in 1 hour
= 2.582 109
= 1.076 108 m
= 1.08 108 m
(iii)Distance moved in 1 second
= 1.076 108
= 3.00 104 m
(b)Speed of the Earth
=km h1
= 1.08 105 km h1
13(a)(i)Angular distance moved in 1 hour
= 360
= 03258
(ii)Angular distance moved in
1 minute
= 360
= 00033
(iii)Angular distance moved in
1 second
= 360
= 00001
(b)Time taken
=days
= 0.039 33 days
= 56.64 min
= 56 min 38 s
(c)Speed
=km h1
= 3680 km h1
Practice 1.2 (p. 27)
1C
2A
3C
4C
5(a)3110 N
(b)The Equator
(c)North Pole or South Pole
612 hours
7(a)All the stars move in circular paths around the north celestial pole. They never rise or set.
(b)
8(a)
The angle between the Sun and the southern horizon is
= 90 22.3 23.5 = 44.2
(b)
The angle between the Sun and the southern horizon is
= 90 22.3 = 67.7
9The Sun moves in a circle around the south celestial pole. It is always at 23.5 from the horizon.
10(a)0
(b)45 N
11
The angle between the southern horizon and the south celestial pole is 3748.
12(a)All the stars move in circular paths around the south celestial pole. They never rise nor set.
(b)
Revision exercise 1
Multiple-choice (p. 31)
1D
2B
38 AU = (38 1.50 1011) m
= 5.70 1012 m
3A
4B
Time between 9:20 p.m. to 10:50 p.m.
= 1.5 hr
Angular distance = 2= rad
5C
6C
Conventional (p. 31)
1(a)1.5 109 km =AU
= 10 AU(1A)
The distance was 10 AU.
(b)Time needed =(1M)
= 5000 s
= 1 hr 23 min 20 s(1A)
2(a)(i)80 000 ly
= (80 000 9.46 1015) m
= 7.57 1020 m(1A)
100 000 ly
= (100 000 9.46 1015) m
= 9.46 1020 m(1A)
The range of diameter of the main disk is 7.57 1020 to 9.46 1020 metres.
(ii)80 000 ly =pc
= 24 500 pc(1A)
100 000 ly =pc
= 30 700 pc(1A)
The range of diameter of the main disk is 24 500 to 30 700 parsecs.
(b)Number of Suns =(1M)
= 6.81 1011(1A)
The maximum number of Suns that can be placed is 6.81 1011.
3(a)V, II, VII, I, VI, III, IV(2A)
(b)Number of planets
=(1M)
= 1.49 1017(1A)
It takes 1.49 1017 planets like the Earth to fill up its diameter.
4(a)Night-time(1A)
(b)Night-time(1A)
(c)Daytime(1A)
5
(Correct paths.)(3 1A)
6(a)City A(1A)
(b)City B(1A)
7(a)Length/distance(1A)
(b)Light year is a large unit. We rarely have measurements in daily life for which such unit is needed. (1A)
(c)The distance between the Sun and a nearby star.(1A)
8(a)Vernal equinox(1A)
(b)The Sun rises straight up exactly in the east, passes right across the sky, and sets straight down exactly in the west. (1A)
9(a)All the stars are seen as moving in semicircles around the north-south axis.(1A)
The stars rise straight up in the eastern half of the horizon, pass right across the sky, and set straight down in the western half of the horizon. (1A)
(b)(i)The Sun rises vertically upwards exactly in the east, passes right across the sky, and sets vertically downwards exactly in the west. It moves along the celestial equator. (1A)
(ii)The Sun rises vertically upwards in a northern east direction. Its path is next to the celestial equator. It sets vertically downwards in a northern west direction. (1A)
(iii)The Sun rises vertically upwards in a southern east direction. Its path is next to the celestial equator. It sets vertically downwards in a southern west direction. (1A)
(Correct paths.)(3 1A)
10(a)The Sun is much larger than the Moon. (1A)
(b)The Sun is much further away than the Moon. Although it is much larger than the Moon, it appears to have the same angular size as the Moon. (1A)
(c)Since the Sun and the Moon has the same angular size, S = M.
=(1M)
=
=
= 391
The ratio is 391 : 1.(1A)
11Speed =km h1(1M)
= 1670 km h1(1A)
=m s1
= 464 m s1(1A)
12(a)A satellite is an object that orbits a planet.(1A)
(b)The Moon (natural satellite of the Earth).(1A)
(c)It orbits the Earth and so it moves against the background of stars in every cycle.(1A)
Therefore it is not fixed on the celestial sphere but traces a path on it.(1A)
13(a)Circumpolar stars of a location are stars that are always above the horizon of that location.(1A)
(b)All the stars move in circular paths around the south celestial pole in clockwise direction.(1A)
(c)Jimmy is correct.(1A)
In summer in the Southern Hemisphere, the Sun is in the southern part of the celestial sphere. (1A)
It stays in the sky for the whole day.(1A)
Since the Sun is much brighter than other stars in the sky, the other stars cannot be seen.(1A)
14(a)
(3 1A)
(b)Nuclear fusion(1A)
15(a)A: Earth(1A)
B: Mars(1A)
C: Saturn(1A)
D: Uranus(1A)
(b)(i)A light year is the distance travelled by light in one year.(1A)
(ii)Distance
= 4 ly
= (4 9.46 1015) m(1M)
= 3.78 1016 m
= 3.78 1013 km(1A)
(iii)Time
=s(1M)
= 1.89 1012 s
=yr(1M)
= 63 000 yr(1A)
(iv)Difficulty of surviving many generations in space.(1A)
Logistics (oxygen, fuel, food, water etc.)(1A)
(Accept other reasonable answers)
16(a)(i)A galaxy is a massive gravitationally bound system which includes stars, stellar clusters, gas and dust, and other matter. (1A)
(ii)600 million years(1A)
(b)A, B and C are correct.(4 1A)
(c)(i)The Moon(1A)
(ii)Any two of the following: spy/ television/photography/astronomy/ communications/meteorology
(2 1A)
(d)(i)A: summer(1A)
C: winter(1A)
D: spring(1A)
(ii)
(Side facing away from the Sun shaded.)(1A)
(Terminator drawn vertically.) (1A)
(iii)X(1A)
Physics in articles (p. 35)
(a)Any one of the following:(1A)
formation of aurora;
strong solar activities affect satellite-based communications, GPS navigation and even electricity transmission;
(Accept other reasonable answers)
(b)Time taken
=(1M)
= 3.75 105 s(1A)
= 4 day 8 hr 10 min
(c)Magnetic force
= BQvsin (1M)
= (3 105)(1.6 1019)(400 103)(sin 90)
= 1.92 1018 N(1A)
The size of the magnetic force acting on the electron is 1.92 1018 N.
(d)Under the influence of the Earth’s magnetic field,(1A)
most charged particles flow to the Earth’s magnetic poles, or the polar regions.(1A)
New Senior Secondary Physics at Work1 Oxford University Press 2011