1. Which of the following does not belong to the solar system?
(a) Asteroids
(b) Comets
(c) Planets
(d) Nebula
[53rd to 55th B.P.S.C. (Pre) 2011]
Ans. (d) Nebula
- Approximately 4.568 billion years ago, the solar system was created.
- It includes the sun, planets, dwarf planets, asteroids, comets, rocks, and dust.
- Nebulae are not a part of the solar system.
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2. Who first propounded that the Sun is the centre of our Solar system and the earth revolves around it?
(a) Newton
(b) Galileo
(c) Panini
(d) Copernicus
[M.P.P.C.S. (Pre) 1995]
Ans. (d) Copernicus
- Nicolaus Copernicus was a Polish scientist, mathematician, and astronomer.
- He wrote a book called ‘Commentariolus’ (Little commentary) in 1514, suggesting that the sun is in the center of the solar system (Heliocentric Theory).
- Interestingly, this same theory had been introduced by Indian astronomers Varahamihira in the sixth century, who said that the moon goes around the earth and the earth revolves around the sun.
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4. Which one of the following statements is correct with reference to our solar system?
(a) The Earth is the densest of all the planets in our solar system
(b) The predominant element in the composition of Earth is silicon
(c) The Sun contains 75 percent of the mass of the solar system
(d) The diameter of the Sun is 190 times that of the Earth
[I.A.S. (Pre) 2002]
Ans. (a) The Earth is the densest of all the planets in our solar system
- Earth has the highest density compared to the other eight planets in our Solar System, which is 5.514 grams per cubic centimeter.
- The densities of the other planets are Mercury (5.42), Venus (5.24), Mars (3.93), Jupiter (1.32), Saturn (0.68), Uranus (1.27), and Neptune (1.63).
- Iron is the largest element in Earth’s composition, making up 32.07%.
- Oxygen is the second largest element, making up 30.12%, and Silicon is the third largest element, making up 15.12%.
- The sun makes up almost all of the solar system and is about 109 times the size of the Earth.
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5. The number of planet in the solar system is –
(a) 7
(b) 9
(c) 12
(d) 21
[U.P.P.C.S. (Pre) 1992]
Ans. (b) 9 (now 8)
- According to old recognition, there are total of 9 planets which are in increasing order of distance from the sun, as follows :
- Mercury (57.9 million Km.)
- Venus (108.2 million Km.)
- Earth (149.6 million Km.)
- Mars (227.9 million Km.)
- Jupiter (778.6 million Km.)
- Saturn (1433.5 million Km.)
- Uranus (2872.5 million Km.)
- Neptune (4495.1 million Km.)
- Pluto (5906.4 million Km.)
NOTE : At an International Astronomical Union meeting in Prague in 2006, a resolution was passed where a definition of a planet was declared and Pluto was no longer considered one of the nine planets, making the total number of planets eight. Pluto is now classified as a dwarf planet. |
6. Which of the given two planets are between Mars and Uranus in order of distance from the sun?
(a) Earth and Jupiter
(b) Jupiter and Saturn
(c) Saturn and Earth
(d) Saturn and Neptune
[I.A.S. (Pre) 2008]
Ans. (b) Jupiter and Saturn
- Two planets between Mars and Uranus in order of distance from the sun are –
- Jupiter (778.6 million Km)
- Saturn (1433.5 million Km)
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7. Arrange the planets given below in order of increasing distance from sun.
1. Pluto
2. Earth
3. Jupiter
4. Uranus
Codes :
(a) 2,3,4,1
(b) 4,3,2,1
(c) 3,2,4,1
(d) 1,2,4,3
[U.P. Lower Sub. (Spl.) (Pre) 2003, U.P. Lower Sub. (Pre) 2002]
Ans. (a) 2, 3, 4, 1
Increasing order of distance from the sun are :
- Mercury (57.9 million Km.)
- Venus (108.2 million Km.)
- Earth (149.6 million Km.)
- Mars (227.9 million Km.)
- Jupiter (778.6 million Km.)
- Saturn (1433.5 million Km.)
- Uranus (2872.5 million Km.)
- Neptune (4495.1 million Km.)
- Pluto (5906.4 million Km.)
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8. The Planets between Earth and Sun are –
(a) Mars and Mercury
(b) Mars and Venus
(c) Mercury and Venus
(d) Jupiter and Saturn
[U.P.P.S.C. (GIC) 2010]
Ans. (c) Mercury and Venus
- The planets go in this order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
- So, the two planets between Earth and the Sun are Mercury and Venus.
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9. The Earth is located between –
(a) Venus and Mars
(b) Mars and Jupiter
(c) Venus and Jupiter
(d) Mercury and Venus
[U.P.P.C.S. (Mains) 2012]
Ans. (a) Venus and Mars
- Earth is the third planet from the Sun, located between Venus and Mars.
- It is the fifth largest planet in our solar system.
- The equator is an imaginary line that splits the planet into two halves, and the diameter of the Earth is about 8,000 miles.
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10. What is true about planets?
(a) Planets are non-luminous bodies and don’t shine
(b) Planets shine though they are non-luminous bodies
(c) Planets do not shine though they are the luminous body
(d) Planets are the luminous body and also shine
[U.P. P.C.S. (Pre) 1992]
Ans. (b) Planets shine though they are non-luminous bodies
- Planets do not produce their own light, but they appear to shine because they reflect the Sun’s light.
- Therefore option (b) is the correct answer.
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11. Match List-I with List-II and select the correct answer by using the codes given below the lists:
| List-I (Special characteristic) |
List- II (Name of the planet) |
| A. Smallest planet in the solar system |
1. Mercury |
| B. Largest planet of the solar system |
2. Venus |
| C. Planet second to the sun in the solar system |
3. Jupiter |
| D. Planet nearest to the sun |
4. Pluto |
|
5. Saturn |
Code :
A B C D
(a) 2 3 5 1
(b) 3 5 1 2
(c) 4 1 2 3
(d) 4 3 2 1
[I.A.S. (Pre) 1998]
Ans. (d) 4 3 2 1
- The correctly matched list is as follows :
| (Special Characteristics) |
(Name of Planets) |
| Smallest planet of the |
Pluto (After it was removed from the group of planets Mercury is the smallest). |
| Largest planet of the solar system |
Jupiter system |
| Planet second nearest to the Sun |
Venus in the solar system |
| The planet nearest to the Sun |
Mercury |
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12. The planet nearest to the sun is –
(a) Mercury
(b) Earth
(c) Venus
(d) Pluto
[U.P.P.C.S. (Mains) 2004]
Ans. (a) Mercury
- Mercury is the planet that is closest to the sun and is also the smallest planet in the solar system.
- It is only a little bit bigger than the moon that orbits Earth.
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13. Which of the following pairs is not properly matched?
(a) The largest planet of the Solar System – Jupiter
(b) The smallest planet of the Solar System – Mercury
(c) The brightest planet of the Solar System – Venus
(d) The slowest moving planet of Solar System – Mars
[U.P.PC.S. (Mains) 2011]
Ans. (d) The slowest moving planet of Solar System – Mars
- Out of the choices given, only (d) is not correct.
- Neptune is the slowest planet in the solar system and takes 165 years to go around the sun once.
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14. Arrange the following in decreasing order of size and select the correct answer from the codes given below :
1. Jupiter
2. Uranus
3. Earth
4. Saturn
Code :
(a) 1, 4, 3, 2
(b) 4, 1, 2, 3
(c) 1, 4, 2, 3
(d) 4, 1, 3, 2
[M.P.P.C.S. (Pre) 2008]
Ans. (c) 1, 4, 2, 3
- The planets are listed from largest to smallest as Jupiter, Saturn, Uranus, Earth, Neptune, Venus, Mars, and Mercury.
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15. Hydrogen, Helium and Methane are the main gases present on
(a) Uranus, Neptune and Pluto
(b) Jupiter, Saturn and Mars
(c) Uranus, Neptune and Venus
(d) Mars and Venus
[U.P.P.C.S. (Mains) 2004]
Ans. (*)
- The planets Jupiter, Saturn, Uranus and Neptune all contain Hydrogen, Helium and Methane gases.
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17. ‘The term ‘Goldilocks Zone’ is often seen in the news in the context of
(a) The limits of the habitable zone above the surface of the Earth
(b) Regions inside the Earth where shale gas is available
(c) Search for the Earth-like planets in outer space
(d) Search for meteorites containing precious metals
[I.A.S. (Pre) 2015]
Ans. (c) Search for the Earth-like planets in outer space
- In Astronomy, the area around a star where the temperature is perfect for liquid water to exist is called the “Goldilocks Zone”.
- Earth is the only planet in our solar system that can support life, and it is the only planet in the Goldilocks Zone of the solar system.
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18. Match list – I with list –II and choose the correct answer by using the codes given below –
List – I List- II
(A) Planet 1. Moon
(B) Satellite 2. Uranus
(C) Comet 3. Mariner
(D) Planetoid or artificial Satellite 4. Halley
Code :
A B C D
(a) 2 1 4 3
(b) 1 2 3 4
(c) 4 3 1 2
(d) 2 1 3 4
[U.P.P.C.S. (Pre) 1999]
Ans. (a) 2 1 4 3
- Uranus is a planet, the Moon is a natural satellite, Halley is a comet and Mariner is an asteroid or man-made satellite.
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19. Which of the following statements are correct regarding the solar system?
I. Mercury is the hottest planet in the solar system
II. Ganymede, satellite of Saturn, is the largest satellite in the solar system
III. Neptune is surrounded by methane gas rings of sub-zero temperature
IV. Phobos and Deimos are two satellites of Mars
(a) Only I and II are correct
(b) Only II and III are correct
(c) Only III and IV are correct
(d) I, II, III and IV all are correct
[Chhattisgarh P.C.S. (Pre) 2020]
Ans. (c) Only III and IV are correct
- Venus is the hottest planet in our solar system, not Mercury.
- This is because of its thick atmosphere trapping heat on its surface, which reaches 464ºC.
- Ganymede is the biggest moon, but it orbits Jupiter, not Saturn.
- Neptune is covered by cold methane gas.
- Mars has two small moons, Phobos and Deimos, which are named after the horses that were driven by the Greek god of war, Ares.
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III. The Sun
1. Which of the following statements is true regarding earth movement?
1. Earth rotates on its axis from west to east resulting into seasonal changes.
2. Earth’s revolution around sun results in the occurrence of day and night on Earth.
(a) Both 1 and 2 are true
(b) Only 2 is true
(c) Both 1 and 2 are false
(d) Only 1 is true
[Jharkhand P.C.S. (Pre) 2021]
Ans. (c) Both 1 and 2 are false
- The earth spins on its axis from west to east, causing nights and days.
- It also revolves around the sun, which causes the changing of seasons.
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2. The substances present at the centre of the sun are in:
(a) Solid, liquid and gaseous states
(b) Liquid state only
(c) Gaseous state only
(d) Both liquid and gaseous state
[U.P.P.C.S.(Pre) 2001]
Ans. (*)
- The temperature of the centre of the the sun is very high (nearly 15000000o C) and because of such a high temperature, all the substance present at the Center of the sun are in the form of Gas and Plasma.
- Plasma is the fourth state of a matter. Thus, none of given answers is correct.
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3. Solar energy is due to –
(a) Ionization
(b) Nuclear Fusion
(c) Nuclear Fission
(d) Oxidation
[U.P.P.C.S. (Pre) 2006, U.P.P.C.S.(Pre) 2001, U.P.P.C.S. (Pre) 1996]
Ans. (b) Nuclear Fusion
- Nuclear reactions come in two forms:
- In fission, a large nucleus splits into two or more smaller nuclei, and in fusion, two or more small nuclei join together to form a larger nucleus.
- The energy, heat, and light released by stars is the result of nuclear fusion.
- In this process, one hydrogen atom combines with another to form a helium atom and energy.
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4. Diamond Ring is a phenomenon observed :
(a) At the start of a total solar eclipse
(b) At the end of a total solar eclipse
(c) Only along the peripheral regions of the totality trail
(d) Only in the central regions of the totality trail
[I.A.S. (Pre) 1996]
Ans. (c) Only along the peripheral regions of the totality trail
- At the start and end of a total solar eclipse, there is a special visual effect called the diamond-ring effect.
- It looks like a ring with a sparkling diamond inside it, as the last bits of sunlight go through the moon’s edge and the faint halo around the sun is just becoming visible.
- A total solar eclipse only lasts for up to 7.5 minutes.
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5. The solar eclipse occurs on –
(a) Quarter Moon day
(b) New Moon day
(c) Any day
(d) Full Moon day (Poornima)
[U.P.P.C.S. (Pre) 1991]
Ans. (b) New Moon day
- When the Moon passes between the Earth and the Sun, a solar eclipse occurs.
- This only happens during the New Moon phase, when the Moon’s shadow falls on the Earth.
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6. Every solar eclipse occurs on –
(a) Poornima only
(b) Amavasya only
(c) (a) and (b)
(d) Neither (a) nor (b)
[U.P. U.D.A./L.D.A. (Pre) 2006, R.A.S./R.T.S. (Pre) 2000, R.A.S./R.T.S. (Pre) 1999]
Ans. (b) Amavasya only
- When the Moon is in its New Moon phase (Amavasya), it blocks the Sun’s light from reaching the Earth, creating a shadow and causing a solar eclipse.
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7. When does a solar eclipse occur?
(a) When the sun comes between the earth and the moon.
(b) When the earth comes between the sun and the Moon.
(c) When the moon comes between the earth and the sun
(d) None of the above
[47th B.P.S.C (Pre) 2005, M.P.P.C.S. (Pre) 1993, U.P.P.C.S. (Pre) 1990]
Ans. (c) When the moon comes between the earth and the sun
- A solar eclipse happens when the Moon passes between the Earth and the sun.
- This can only happen when the Moon is in the New Moon phase, when it is directly in line with the Sun and Earth, and casts a shadow on the Earth.
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8. The Solar Eclipse achieves totality only in limited geographical regions because –
(a) The size of the shadow of the Moon on the Earth is small as compared to the cross section of the Earth.
(b) The Earth is not a smooth flat surface but has elevations and depressions.
(c) The trajectories of the Earth around the Sun and the Moon around the Earth are not perfect circles.
(d) Sun rays can reach most of the peripheral regions of the shadow of the Moon due to atmospheric refraction.
[I.A.S. (Pre) 1993]
Ans. (a) The size of the shadow of the Moon on the Earth is small as compared to the cross section of the Earth.
- When the moon moves in front of the Sun, it causes a solar eclipse.
- Since the moon’s shadow is smaller than the Earth, the total eclipse is only visible in certain parts of the world.
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9. The sun’s halo is produced by the refraction of light in –
(a) Water vapour in stratus clouds
(b) Ice crystals in cirrocumulus clouds
(c) Ice crystals in Cirrus clouds
(d) Dust particles in Stratus clouds
[I.A.S. (Pre) 2002]
Ans. (c) Ice crystals in Cirrus clouds
- When the sun’s light passes through the ice crystals in the top layer of cirrus clouds, a circle appears around the sun, called a halo.
- This is because the sun’s rays are being refracted.
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10. One Astronomical unit is average distance –
(a) Between Earth and Sun
(b) Between Earth and Moon
(c) Between Jupiter and Sun
(d) Pluto and Sun
[Jharkhand P.C.S. (Pre) 2011, I.A.S. (Pre) 1998]
Ans. (a) Between Earth and Sun
- The average distance between the Earth and the Sun is called an astronomical unit.
- 1 AU = 149.598 million kilometers or 149.6 million kilometers.
- In Meter –> 1 AU = 149.598 × 109
- In millimeter –> 1 AU = 149.59 × 1012
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11. The average or mean distance between the Earth and the sun is –
(a) 70 × 155 Km
(b) 100 × 105 Km
(c) 110 × 106 Km
(d) 150 × 106 Km
[I.A.S. (Pre) 1997]
Ans. (d) 150 × 106 Km
- The average distance between the Earth and the Sun is called an astronomical unit.
- 1 AU = 149.598 million kilometers or 149.6 million kilometers.
- In Meter –> 1 AU = 149.598 × 109
- In millimeter –> 1 AU = 149.59 × 1012
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12. The distance between the earth and the sun is –
(a) 107.7 Million Km
(b) 142.7 Million Km
(c) 146.6 Million Km
(d) 149.6 Million Km
[U.P.P.C.S. (Pre) 2010]
Ans. (d) 149.6 Million Km
- The Earth and the Sun are typically about 93 million miles (150 million km) apart.
- This measurement is known as one astronomical unit (1 AU).
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13. The earth is nearest to the sun on –
(a) 3rd January
(b) 4th July
(c) 22nd March
(d) 21st September
[U.P.P.S.C. (GIC) 2010, Uttarakhand P.C.S. (Mains) 2006]
Ans. (a) 3rd January
- At the beginning of January, the sun is closest to the Earth.
- This is known as ‘Perihelion’, usually happening on January 4th.
- On the other hand, when the sun is farthest away from the Earth on July 4th, this is known as ‘Aphelion’.
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14. The size of the Sun is how many times bigger than that of the earth?
(a) 124 times
(b) 100 times
(c) 109 times
(d) 115 times
[M.P.P.C.S. (Pre) 2014]
Ans. (c) 109 times
- NASA says the sun is 109.2 times bigger than the Earth.
- The sun’s middle is 695508 km across and the Earth’s middle is 6378 km in size.
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IV. The Mercury
1. Which of the following planets takes the least time to orbit the sun:
(a) Pluto
(b) Mercury
(c) Earth
(d) Saturn
[U.P.P.C.S. (Pre) 2002]
Ans. (b) Mercury
- Mercury takes the least amount of time to go around the Sun compared to the other eight planets.
- Here’s how long each planet takes to make one orbit:
- Mercury – 87.96 Days
- Venus – 224.68 Days
- Earth – 365.26 Days
- Mars – 686.98 Days
- Jupiter – 11.862 Years
- Saturn – 29.456 Years
- Uranus – 84.07 Years
- Neptune – 164.81 Years
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2. The two planets having no satellites are :
(a) Earth and Jupiter
(b) Mercury and Venus
(c) Mercury and Saturn
(d) Venus and Mars
[U.P. Lower Sub. (Pre) 2009, U.P.P.C.S. (Pre) 1999]
Ans. (b) Mercury and Venus
- There are only two planets in our solar system having no natural satellite which are –
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3. Which of the following planets does not have a satellite?
(a) Earth
(b) Mars
(c) Jupiter
(d) Venus
[U.P. Lower Sub. (Mains) 2013]
Ans. (d) Venus
- Only Mercury and Venus in our solar system don’t have any moons.
- Mercury is the closest planet to the sun and the smallest one.
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4. The albedo of Mercury is much greater than the albedo of the Earth. Which of the statements given above is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
[I.A.S. (Pre) 2008]
Ans. (a) 1 only
- The brightness of planets is usually measured by a value called albedo.
- Mercury is hit by more sunlight than Earth, but its albedo is lower.
- Mercury’s albedo is 0.138, while Earth’s is 0.367.
- This means that statement 1 is accurate and option A is the correct choice.
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V. The Venus
1. The hottest planet in the solar system is –
(a) Mercury
(b) Venus
(c) Mars
(d) Earth
[41st B.P.S.C. (Pre) 1996]
Ans. (b) Venus
- Average temperature of all Planet in our Solar System is as follows –
- Mercury = 167ºC
- Venus = 464ºC
- Earth = 15ºC
- Mars = – 63ºC
- Jupiter = –110ºC
- Saturn = –140º C
- Uranus = –195ºC
- Neptune = –200ºC
- Thus, Venus is the hottest planet in our Solar System and Neptune is the coldest planet.
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2. Which planet is known as the ‘Evening Star’?
(a) Mars
(b) Jupiter
(c) Venus
(d) Saturn
[44th B.P.S.C. (Pre) 2000]
Ans. (c) Venus
- Venus is called the Evening Star and the Morning Star, Mars is known as the Red Planet, and Saturn has a set of rings called Saturn’s Rings.
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3. Which one of the following is known as ‘Morning Star’?
(a) Mercury
(b) Venus
(c) Mars
(d) Saturn
[U.P. Lower Sub. (Pre) 2015]
Ans. (b) Venus
- Venus is known as the “Morning Star” and “Evening Star” because it is the brightest planet.
- It is also referred to as the “twin sister” of earth because Venus and earth are almost the same size, mass, and composition.
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4. Assertion (A): The existence of human life on Venus is highly improbable.
Reason (R): Venus has an extremely high level of carbon dioxide in its atmosphere.
Code :
(a) Both A and R are true, and R is the correct explanation of A
(b) Both A and R are true, and R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
[I.A.S. (Pre) 2005]
Ans. (a) Both A and R are true, and R is the correct explanation of A
- Research has shown that the atmosphere of Venus is made up mostly of carbon dioxide (CO2) and the surface temperature is extremely hot (over 400 degrees Celsius).
- This means that life on Venus is highly unlikely due to the CO2 and the high temperatures.
- Both the statement and the reason for this are correct.
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5. The planet which is called the twin sister of the earth is –
(a) Mercury
(b) Venus
(c) Mars
(d) Pluto
[U.P. Lower Sub. (Pre) 2008, U.P.P.C.S. (Pre) 2007]
Ans. (b) Venus
- Venus is like a twin sister to Earth and is the brightest planet in the sky.
- It’s known as the Morning Star and Evening Star, too.
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6. The Spacecraft “Magellan” was sent to –
(a) Pluto
(b) Saturn
(c) Mars
(d) Venus
[U.P.P.C.S. (Pre) 1991]
Ans. (d) Venus
- The Magellan spacecraft was sent to map the surface of Venus.
- It was named after the Portuguese explorer, Ferdinand Magellan, and took off on May 4, 1989, arriving in Venus’ orbit on August 10, 1990.
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VI. The Earth
1. Who amongst the following was the first to state that the Earth was spherical?
(a) Aristotle
(b) Copernicus
(c) Ptolemy
(d) Strabo
[I.A.S. (Pre) 2001]
Ans. (a) Aristotle
- Aristotle was a Greek philosopher and scientist who lived from 384 to 322 BC.
- In one of his books, “On the Heavens”, he wrote that the Earth is round.
- This book was translated into English by J.L. Stock.
- Later on, other philosophers such as Ptolemy, Strabo, and Copernicus also supported this idea.
- Therefore, Aristotle was the first to suggest that the Earth is a sphere.
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2. In the form of the organism, the Scientific name of Earth is –
(a) Cow
(b) Sita
(c) Green Planet
(d) Harmij
[U.P.P.C.S. (Pre) 1999]
Ans. (c) Green Planet
- Life on Earth exists because of the environment.
- Earth is often called the Green Planet because of its ecology.
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3. The diameter of the Earth is –
(a) 8,000 km
(b) 1,00,000 km
(c) 12,800 km
(d) None of the above
[Uttarakhand P.C.S. (Mains) 2006]
Ans. (c) 12,800 km
- The width of the Earth at the equator is 12,756 kilometers and the width at the poles is 12,714 kilometers.
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4. Statement (A): Moving from one place on earth to another place of high latitude, the weight of an object decreases.
Reason (R): Earth is not a perfect sphere.
Choose the correct answer by using code given below –
(a) (A) and (R) both are true, and (R) explains (A) properly.
(b) (A) and (R) both are true, but (R) does not explains
(A) properly.
(c) (A) is true, but (R) is wrong.
(d) (A) is false, but (R) is true.
[I.A.S. (Pre) 2003]
Ans. (d) (A) is false, but (R) is true.
- The force caused by the Earth spinning around its axis is strongest at the equator.
- This means that the weight of something is smallest at the equator and biggest at the poles, and it gets heavier the further away from the equator you go.
- This means statement A is incorrect.
- The Earth’s shape is closest to an oblate spheroid, which is also called a Geoid.
- This means the Earth isn’t a perfect sphere, so Reason R is correct.
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5. Unlike the fluid core of the Earth, the core of the moon is–
(a) Plasma
(b) Volatile gas
(c) Viscous liquid
(d) Solid
[U.P.P.C.S. (Mains) 2004]
Ans. (c) Viscous liquid
- The Moon has a liquid core, just like the Earth does.
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6. A chemical element found in abundance in the Earth’s crust is–
(a) Oxygen
(b) Aluminium
(c) Iron
(d) Silicon
[U. P.U.D.A./L.D.A. (Pre) 2013]
Ans. (a) Oxygen
- Oxygen is an element that is found a lot in the Earth’s surface.
- The amount of different elements in the Earth’s crust is listed below :
| (Element) |
(Percentage) |
| Oxygen (O) |
46.60 |
| Silicon (Si) |
27.72 |
| Aluminium (Al) |
8.13 |
| Iron (Fe) |
5.00 |
| Calcium (Ca) |
3.63 |
| Sodium (Na) |
2.83 |
| Potassium (K) |
2.59 |
| Magnesium (Mg) |
2.09 |
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7. Time taken by light emitted from sun to reach earth is –
(a) 2 minutes
(b) 1 minutes
(c) 8 minutes
(d) 16 minutes
[U.P.P.C.S. (Mains) 2005, M.P.P.C.S. (Pre) 1996, 38th B.P.S.C. (Pre) 1992]
Ans. (c) 8 minutes
- Sunlight, which is the radiation from the Sun, is made up of electromagnetic waves.
- It takes about 8 minutes and 19 seconds for the energy waves to arrive at Earth, traveling at 186,000 miles per second.
- Option (c) is the correct answer.
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8. Which one of the following Stars is nearest to the Earth?
(a) Polaris
(b) Alpha Centauri
(c) Sun
(d) Sirius
[I.A.S. (Pre) 1997]
Ans. (c) Sun
- The Sun is the closest star to us, about 149.6 million kilometers away. Polaris is very far, about 434 light years (newly estimated to be 323 light years) away from us, and Sirius is 8.6 light years away. Alpha Centauri is the closest star after the Sun, only 4.35 light years away.
|
9. Which of the following planets is nearest to Earth?
(a) Pluto
(b) Mars
(c) Saturn
(d) Jupiter
[M.P.P.C.S. (Pre) 1993]
Ans. (b) Mars
- The list of planets in increasing order of distance from Earth is–
- Venus – 41.4 Million Km
- Mars – 78.3 Million Km
- Mercury – 91.7 Million Km
- Jupiter – 628.7 Million Km
- Saturn – 1277.4 Million Km
- Uranus – 1634.4 Million Km
- Neptune – 4347.5 Million Km
- Since Venus is not an option, the correct answer is Mars.
|
10. The planet nearest to the Earth is –
(a) Venus
(b) Mercury
(c) Mars
(d) Jupiter
[U.P.P.C.S. (Pre) 1991, U.P.P.C.S. (Pre) 1993, U.P.P.C.S. (Pre) 1997, Uttarakhand P.C.S. (Pre) 2002, U.P.P.C.S. (Pre) 2012]
Ans. (a) Venus
- Mercury is the planet closest to Earth.
- People used to think Venus was the planet closest to us, but it is only closest when it is between Earth and the Sun during its orbit.
|
11. In completing one revolution of the sun, Earth takes approximately –
(a) 365 days
(b) 365.25 days
(c) 365.5 days
(d) 365.75 days
[41st B.P.S.C. (Pre) 1996]
Ans. (b) 365.25 days
- The Earth takes 365.25636 days (or 365 days, 6 hours 9 minutes and 9.51 seconds) to go all the way around the Sun.
- This is called a ‘Solar day’ or a ‘Tropical year’, which is 365.25 days long.
- In 2000, the time it took was a bit longer – 365 days, 6 hours 13 minutes (instead of 9 minutes) and 53.26 seconds (instead of 9.51 seconds).
- This is called an ‘Anomalistic Year’.
|
12. At which average speed the Earth revolves around the Sun?
(a) 20 Km/ sec
(b) 30 Km/ sec
(c) 40 Km/ sec
(d) 50 Km/ sec
[I.A.S. (Pre) 2006]
Ans. (b) 30 Km/ sec
- Earth circles around the Sun, moving at a speed of about 30 Km/sec.
- This speed is similar to the speed of light.
- The orbital velocity of other planets is also around this speed.
|
13. Approximately how much distance per minute does the earth cover while revolving?
(a) 49 km
(b) 59 km
(c) 69 km
(d) 79 km
[44th B.P.S.C. (Pre) 2001]
Ans. (*)
- The circumference of Earth at the equator is around 40,090 Km.
- This is the distance Earth travels in a day, so its speed on its axis is about 1670 Km per hour, or 27.8 Km per minute.
- None of the answers given are correct.
|
14. The equatorial circumference of the Earth is nearly
(a) 31,000 km
(b) 40,000 km
(c) 50,000 km
(d) 64,000 km
[Uttarakhand P.C.S. (Pre) 2016]
Ans. (b) 40,000 km
- Earth’s equator is about 40,090 km long.
- This distance is covered by Earth in 24 hours, so its speed on its axis is about 1670 km/hour.
- That’s 27.8 km/minute, so none of the given answers is correct.
|
15. Earth’s axis is tilted at an angle of –
(a) 23 1/20
(b) 66 1/20
(c) 33 1/20
(d) 42 1/20
[M.P.P.C.S. (Pre) 1990]
Ans. (a) 23 1/20
- Earth is tilted at an angle and it spins around its axis very quickly – about 1000 miles per hour.
- This means that it takes about 24 hours for Earth to make one full rotation.
|
16. The Earth’s axis of rotation (polar axis) is always inclined at an angle of
(a) 23.0o from the elliptic axis
(b) 23.1o from the elliptic axis
(c) 24.5o from the elliptic axis
(d) 23.5o from the elliptic axis
[U.P.P.C.S. (Pre) 2016]
Ans. (d) 23.5o from the elliptic axis
- The Earth spins around an imaginary line which goes through the North and South Poles of the planet.
- This line is known as the axis of rotation.
- The Earth’s axis is always tilted at an angle of 23.5 degrees away from the elliptic axis.
|
17. Consider the following statements :
1. The axis of the earth’s magnetic field is inclined at 23 and a half degree to the geographic axis of the earth.
2. The earth’s magnetic pole in the northern hemisphere is located on a peninsula in northern Canada.
3. Earth’s magnetic equator passes through Thumba in South India.
Which of the Statements given above is/are correct?
(a) 1, 2 and 3
(b) 2 and 3
(c) 2 only
(d) 3 only
[I.A.S. (Pre) 2005]
Ans. (d) 3 only
- The Earth’s magnetic field’s axis is not the same everywhere and is not always inclined at 23 degrees.
- This makes statement 1 incorrect.
- The magnetic pole of the Earth in the Northern hemisphere used to be in Queen Elizabeth Island in Northern Canada and not on a peninsula, making statement 2 incorrect.
- Thumba is a good spot to launch satellites because of its close proximity to the geomagnetic equator, which is why the Thumba Equatorial Rocket Launching Station (TERLS) was built there.
- This makes statement 3 true, and option (d) is the correct answer.
|
18. Consider the following statements :
1. The Earth’s magnetic field has reversed every few hundred thousand years.
2. When the Earth was created more than 4000 million years ago, there was 54% oxygen and no carbon dioxide
3. When living organisms originated, they modified the early atmosphere of the Earth.
Which of the statements given above is/are correct?
(a) 1 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3
[I.A.S. (Pre) 2018]
Ans. (c) 1 and 3 only
- European Space Agency data suggests that the Earth’s magnetic field might switch around.
- This is because something causes a change in the movement of the Earth’s molten core, which causes the North and South poles to reverse.
- The Earth is around 5 billion years old, and in the beginning there was no oxygen in the air.
- Around 4 billion years ago, water vapor in the air condensed and formed the hydrosphere, and around 1 billion years ago, early aquatic animals like algae came into existence.
- These algae were autotrophs, which means they could create their own food, and this process of photosynthesis released free oxygen into the atmosphere.
- This oxygen in the upper layers of the atmosphere created ozone.
|
19. Consider the following statements and select the correct answer from the codes given below:
1. The northern end of the earth’s axis is called the North Pole.
2. 45o latitude is half of the length of the equator.
3. There is the parallelism of the earth’s axis.
4. The earth’s speed of revolution is faster in the aphelion position.
Code :
(a) 1 and 2
(b) 2 and 3
(c) 3 and 4
(d) 1 and 3
[U.P.P.C.S. (Pre) 2000]
Ans. (d) 1 and 3
- The North Pole is the northernmost point on Earth, located at the northern end of the Earth’s axis, Statement 1 is correct.
- The 45° parallel line is 28343.892 km long, and the equator is 40090.28 km long, so the 45° parallel is not half the length of the equator and statement 2 is incorrect.
- Parallelism of the Earth’s axis means that as the Earth orbits the Sun, its axis stays in the same position, Statement 3 is correct.
- The Aphelion happens on 4 July, when the distance between the Sun and Earth is the greatest and the Earth’s speed is slowest.
- Statement 4 is false.
|
20. The causes of Day and Night is –
(a) Earth-rotation
(b) Rotation of Earth on its axis
(c) Tilt of Earth’s axis
(d) Moon’s rotation
[R.A.S./R.T.S. (Pre) 2000, R.A.S./R.T.S. (Pre) 1999]
Ans. (b) Rotation of Earth on its axis
- The Earth rotates on its axis, taking about 24 hours to complete one rotation.
- This causes day and night, as the Sun is visible when the place on Earth is facing it, and it is dark when the place is facing away from the Sun.
|
21. Who among the following was the first to explain that the rotation of the earth on its own axis accounts for the daily rising and setting of the Sun?
(a) Aryabhata
(b) Bhaskara
(c) Brahmagupta
(d) Varahamihira
(e) None of the above/More than one of the above
[64th B.P.S.C. (Pre) 2018]
Ans. (a) Aryabhata
- Aryabhatta discovered that the earth turning on its own axis is why we can see the sun rise and set every day.
- His work is found in the Arya Siddhanta.
- Bhaskara agreed with the Bhedabheda School of Vedanta Philosophy and wrote about Brahma sutras and Maya.
- Varahamihira wrote Brihat Samhita and Pancha Siddhantika.
|
22. When the length of day and night is equal the Sunrays falls perpendicular at –
(a) North pole
(b) Equator
(c) South pole
(d) Tropic of cancer
[Uttarakhand P.C.S. (Pre) 2002]
Ans. (b) Equator
- Twice a year, on March 21st and September 23rd, the sun is directly above the equator and day and night are each 12 hours long in both hemispheres.
|
23. Seasonal changes are caused by which one of the special characteristic of Earth’s motion ?
(a) Revolution around Sun
(b) Axial tilt by 23 degree
(c) (a) and (b) both
(d) Rotation on its axis
[R.A.S./R.T.S. (Pre) 1992]
Ans. (c) (a) and (b) both
- The main cause of the changing seasons is the fact that Earth is tilted on its axis at an angle of 23° and it revolves around the Sun.
- The distance between Earth and the Sun also has a slight effect on the seasonal variations.
|
24. What causes the change of Seasons?
(a) Earth’s Rotation and revolution
(b) Earth’s Revolution
(c) Earth’s Revolution and Inclination of its Axis
(d) Earth’s Rotation and inclination of its Axis
[Jharkhand P.C.S. (Pre) 2013]
Ans. (c) Earth’s Revolution and Inclination of its Axis
- The main cause of the changing seasons is the Earth’s tilt of 23 degrees and its orbit around the Sun.
- The distance between the Earth and Sun also plays a small part in the changing seasons.
|
25. Consider one special point at the Earth’s surface (eg. City Delhi) its temperature at noon (eg. 12 o’clock) will be higher in Summer in comparison to winter because-
(a) Earth is much closer to Sun in Summer in comparison to winter.
(b) In winter the Sun rays falling on the Earth bends more towards the Earth’s surface in Comparison to the summer.
(c) The vaporization of water happens only in winter due to environmental precipitation
(d) In winters the Earth’s axis becomes more inclined towards Sun.
[I.A.S. (Pre) 1993]
Ans. (b) In winter the Sun rays falling on the Earth bends more towards the Earth’s surface in Comparison to the summer.
- Twice a year, on March 21st and September 23rd, the Sun’s rays hit the Equator directly.
- From March 21st to September 23rd, the Sun will be between the Equator and the Tropic of Cancer, meaning that summer will be in the Northern Hemisphere and winter in the Southern Hemisphere.
- For the next period, from September 23rd to March 21st, the Sun will be between the Equator and the Tropic of Capricorn.
- During this time, the Sun’s rays will be more slanted in the Northern Hemisphere than the Southern Hemisphere, meaning summer will be in the Southern Hemisphere and winter in the Northern Hemisphere.
- Because of this, the temperature in Delhi, which is in the Northern Hemisphere, will be higher in the summer than in the winter.
|
26. If the distance between the sun and the earth is reduced by quarter to present distance, then probability of which one will increase –
(a) Earth would fall into Sun.
(b) Earth shall be burned.
(c) The duration of our year will be decreased.
(d) Earth will fly into space.
[R.A.S./R.T.S. (Pre) 1993]
Ans. (c) The duration of our year will be decreased.
- If the Sun and Earth are moved closer together by a quarter of the current distance, the Earth’s orbit around the Sun will be smaller and the length of the year will be less than 365 days.
- The Earth will also move faster since it is closer.
|
27. The possibility of a desert on earth is more
(a) Nearby 0° latitude
(b) Nearby 23° latitude
(c) Nearby 50° latitude
(d) Nearby 70° latitude
[41st B.P.S.C. (Pre) 1996]
Ans. (b) Nearby 23° latitude
- Desert climate is sometimes called arid climate. Most deserts have a tropical climate, which generally falls between 15-30º latitude. There are four main geographical conditions that cause deserts to form are –
- At around 300 degrees latitude, there is usually a lot of air pressure. This climate is seen in the Sahara and the deserts of Australia.
- The western side of the continent located between 20-30 degrees latitude has deserts such as Arizona, Mexico, Atacama, and Namibia.
- Death Valley in North America, the Patagonian desert in Argentina, and the Peruvian desert are all deserts located in areas blocked from rain by mountains.
- The desert is found in the middle of the continents, far away from humid air. Examples of this kind of desert include the Gobi Desert (in China and Mongolia), the Australian Desert, and the Great Basin Desert (in the USA).
|
28. Assertion (A): Artificial satellites are always launched from the earth in the eastward direction.
Reason (R): The earth rotates from west to east and so the Satellite attains the escape velocity.
Code :
(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, (R) is not a correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.
[I.A.S. (Pre) 2002]
Ans. (d) (A) is false, but (R) is true.
- It is true that most satellites are launched eastwards from Earth because they gain speed, but that isn’t the case for every launch.
- Satellites intended to orbit the poles are launched in either a north or south direction.
|
29. A Ball thrown outside from an artificial satellite revolving around the Earth will –
(a) Go to the Sun
(b) Go to the Moon
(c) Fall on the Earth
(d) Revolve around the Earth in the same orbit with the same time period as the satellite
[U.P.P.C.S. (Pre) 1995]
Ans. (d) Revolve around the Earth in the same orbit with the same time period as the satellite
- Anything thrown from a satellite will orbit in the same way as the satellite.
|
30. In the structure of planet Earth, below the mantle, the core is mainly made up of which one of the following ?
(a) Aluminium
(b) Chromium
(c) Iron
(d) Silicon
[I.A.S. (Pre) 2009]
Ans. (c) Iron
- The Earth has two layers below its mantle:
- The outer core is made up mostly of liquid iron and nickel and is about 2260 Km thick.
- The inner core is a hot, dense ball of mostly iron with a radius of 1220 Km and a temperature of 5200o C.
|
31. The World Earth Day is celebrated on –
(a) 22 April
(b) 22 March
(c) 07 April
(d) 07 March
[M.P.P.C.S. (Pre) 2015]
Ans. (a) 22 April
- Earth Day is celebrated annually on the 22nd of April to commemorate the beginning of the modern environmental movement in 1970.
- It was first observed in the same year.
|
VII. The Mars
1. The duration of its day and the tilt of its axis are almost identical to those of the Earth. This is true of :
(a) Uranus
(b) Neptune
(c) Saturn
(d) Mars
[U.P.P.C.S.(Pre) 2001, I.A.S. (Pre) 1994]
Ans. (d) Mars
- The length of a day on Earth is 23 hours, 56 minutes, 23 seconds, and its axis is tilted 230 degrees, 27 minutes.
- Mars has a similar day length of 24 hours, 37 minutes, 23 seconds, and its axis is tilted 250 degrees, 12 minutes.
|
2. Assertion (A): To orbit around the Sun the planet Mars takes less time than the time taken by the Earth.
Reason (R): The diameter of the planet Mars is less than that of Earth.
Code :
(a) Both (A) and (R) are true, individually true and (R) is the correct explanation of (A)
(b) Both (A) and (R) are individually true ,but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false
(d) (A) is false, but (R) is true
[I.A.S. (Pre) 2006]
Ans. (d) (A) is false, but (R) is true
- The amount of time a planet takes to go around the Sun depends on how far away it is from the Sun.
- The Sun is 227943824 km away from Mars and 149598262 km away from Earth.
- It takes 365.256 days for Earth to orbit around the Sun and 686.98 days for Mars.
- Statement (A) is wrong.
- The diameter of Mars is 6792 km and Earth’s equatorial diameter is 12756.28 km, so Reason (R) is correct.
|
3. Which one of the following conditions is most relevant for the presence of life on Mars?
(a) Atmospheric composition
(b) Thermal conditions
(c) Occurrence of ice cap and frozen water
(d) Occurrence of ozone
[I.A.S. (Pre) 1997]
Ans. (c) Occurrence of ice cap and frozen water
- At first, Mars was seen as similar to Earth because of the makeup of its atmosphere.
- Mars’ atmosphere is made up of 95.1% Carbon dioxide, 2.59% Nitrogen, 1.94% Argon, 0.16% Oxygen, and 210 ppm water.
- The presence of life on Mars is most likely related to the ice caps and frozen water at the poles.
- The temperature on Mars is usually about the same as on Earth, around -63 degrees Celsius or 260-310 Kelvin.
|
4. Which one of the following may have alien life because of a very conducive environment to life:
(a) Jupiter
(b) Mars
(c) Europa-The Jupiter’s Moon
(d) Moon-The Earth’s Moon
[U.P.P.C.S. (Pre) 2000]
Ans. (b & c) Mars & Europa-The Jupiter’s Moon
- Europe is one of the moons orbiting Jupiter.
- The Voyager mission was launched by Europe to investigate if life could be supported there.
- Europa is icy and has a thick layer of frozen water on its surface, similar to our Earth’s frozen oceans.
- It is believed that the depth of this frozen ocean is about 50 kilometres.
- If this is true, Europa could be the only place in our solar system other than Earth that has such a large amount of water.
|
5. Phoenix Mars Lander landed on the surface of Mars on :
(a) 27 June, 2008
(b) 27 May, 2008
(c) 26 June, 2008
(d) 26 May, 2008
[Chhattisgarh P.C.S. (Pre) 2008]
Ans. (d) 26 May, 2008
- The Phoenix Mars Lander was sent up into space on August 4th, 2007.
- It eventually arrived at the North Pole of Mars on May 26th, 2008 and the mission officially ended on November 11th, 2008.
- Phoenix discovered that there was ice on Mars.
|
VIII. The Jupiter
1. The moons of the Planet Jupiter were discovered by –
(a) Newton
(b) Galileo
(c) Kepler
(d) Copernicus
[Uttarakhand Lower Sub. (Pre) 2010]
Ans. (b) Galileo
- Jupiter is the biggest planet in our solar system.
- Galileo Galilei discovered four of its biggest moons (LO, Europa, Callisto, and Ganymede) in 1610, and they are called the Galilean moons.
|
2. Which is the largest Planet in the Solar System?
(a) Jupiter
(b) Neptune
(c) Uranus
(d) Saturn
[M.P.P.C.S. (Pre) 1996, 41st B.P.S.C. (Pre) 1996, M.P.P.C.S. (Pre) 1990, U.P.P.C.S. (Pre) 1990]
Ans. (a) Jupiter
- According to size planets of our solar system are as follows:
- Jupiter – (Diameter 142,984 Km)
- Saturn ó (Diameter 120,536 Km)
- Uranus ó (Diameter 51,118 Km)
- Neptune ó(Diameter 49,528 Km)
- Earth ó (Diameter 12,756 Km)
- Venus ó (Diameter 12,104 Km)
- Mars ó (Diameter 6,792 Km)
- Mercury ó (Diameter 4,879 Km)
|
3. Which one of the following is the heaviest planet of our Solar System?
(a) Jupiter
(b) Venus
(c) Pluto
(d) Saturn
[Chhattisgarh P.C.S. (Pre) 2003]
Ans. (a) Jupiter
- Jupiter is the biggest planet in our Solar System.
- It has a diameter of 142984 Kilometers and a density of 1.32 gm/cm3.
- It is also the fastest spinning planet in the Solar System.
|
4. Among the following which planet takes maximum time for one revolution around the Sun?
(a) Earth
(b) Jupiter
(c) Mars
(d) Venus
[I.A.S. (Pre) 2003, Chhattisgarh P.C.S. (Pre) 2011]
Ans. (b) Jupiter
- In the given options Jupiter takes maximum time i.e., 11.86 years to complete a revolution around the Sun, Earth takes 365.25 days, Mars takes 686.98 days and Venus takes 24.68 days.
|
5. The ring of Jupiter is composed of –
(a) Silicates
(b) Non-existent
(c) Very thick and opaque
(d) All the above
[U.P.P.C.S. (Mains) 2004]
Ans. (a) Silicates
- In 1979, Voyager 1 Spacecraft discovered Jupiter’s rings for the first time.
- These rings are known as “Jovian rings” and it is thought that they are made of silicates.
- They are quite faint and difficult to spot, but it’s not impossible to see them.
|
6. Which one of the following planets has the largest number of natural satellites or moons?
(a) Jupiter
(b) Mars
(c) Saturn
(d) Venus
[I.A.S. (Pre) 2009]
Ans. (a) Jupiter
- Jupiter is the biggest planet in our Solar System and also has the second highest number of moons.
- Currently, 79 moons of Jupiter have been found.
- Before, the answer to the question about which planet has the most moons is Jupiter, but now Saturn is the correct answer, so choice (c).
- The number of moons for other planets is as follows :
| (Name of the planet) |
(Total moon) |
| Mercury |
0 |
| Venus |
0 |
| Earth |
1 |
| Mars |
2 |
| Jupiter |
79 |
| Saturn |
82 |
| Uranus |
27 |
| Neptune |
14 |
|
IX. The Saturn
1. Time Saturn takes to complete one revolution around the Sun-
(a) 18.5 years
(b) 36 years
(c) 29.5 years
(d) 84 years
[44th B.P.S.C. (Pre) 2000]
Ans. (c) 29.5 years
- It takes Saturn 29.456 years to go all the way around the Sun.
- Therefore, option (c) is the right answer.
|
2. Which of the following planets has rings around it –
(a) Saturn
(b) Mars
(c) Mercury
(d) Earth
[U.P.P.C.S. (Pre) 1990]
Ans. (a) Saturn
- Saturn is known for its unique rings which can be seen from Earth.
- It appears to be yellow in color.
- Additionally, both Jupiter and Neptune have rings.
|
3. After seven years of its journey spacecraft Cassini started its revolution in June-2004 around which planet–
(a) Mercury
(b) Jupiter
(c) Mars
(d) Saturn
[U.P.P.C.S. (Mains) 2004]
Ans. (d) Saturn
- The Cassini spacecraft was sent to Saturn on October 15, 1997 and started orbiting around the planet in June 2004.
|
4. Planet Saturn –
(a) Is colder than Pluto
(b) Is colder than Neptune
(c) Warmer than Neptune
(d) Warmer than Jupiter
[U.P.P.C.S. (Pre) 2010]
Ans. (c) Warmer than Neptune
- Saturn is hotter than Neptune.
- Saturn is nearer to the Sun than Neptune when looking at the order of planets from the Sun (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
- Saturn will be hotter than Neptune.
|
5. Titan is the largest moon of the planet –
(a) Mars
(b) Venus
(c) Jupiter
(d) Saturn
[U.P.U.D.A./L.D.A. (Pre) 2006]
Ans. (d) Saturn
- Titan is the biggest moon orbiting Saturn, with a diameter of 5,150 Km.
- Other major moons around Saturn include Atlas, Epimetheus, Tethys, Lapetus, Dione, Phoebe, Helene and Enceladus.
- The second largest moon of Saturn is Reya, with a diameter of about 1,530 Km.
|
X. The Uranus, Neptune and Pluto
1. For one revolution around the Sun, Uranus takes –
(a) 84 years
(b) 36 years
(c) 18 years
(d) 48 years
[44th B.P.S.C. (Pre) 2000]
Ans. (a) 84 years
- Uranus takes 83.7 years to go around the Sun.
- A day on Uranus is about 17.2 hours long.
|
2. The year is largest on –
(a) Pluto
(b) Jupiter
(c) Neptune
(d) Earth
[39th B.P.S.C. (Pre) 1994]
Ans. (a) Pluto
- Pluto is the planet that takes the longest to go around the Sun because it is the farthest away from it.
- It takes 247.9 years for Pluto to make one orbit.
|
3. Which planet takes the longest period in revolving around the Sun ?
(a) Uranus
(b) Jupiter
(c) Neptune
(d) Pluto
[U.P. Lower Sub. (Spl) (Pre) 2004]
Ans. (d) Pluto
- For the longest time, Neptune has taken to complete one orbit around the Sun.
- Since 2006, Pluto has been excluded from the list of planets, leaving 8 planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.
- The length of time it takes for each of these planets to orbit the Sun is listed below.
| (Celestial Body) |
(Time of Revolution in years) |
| Jupiter |
11.86 |
| Uranus |
83.7 |
| Neptune |
163.7 |
| Pluto |
247.9 |
|
4. According to a new definition adopted by ‘International Astronomical Union’ in 2006, which of the following is not a ‘planet’?
(a) Uranus
(b) Neptune
(c) Pluto
(d) Jupiter
[M.P.P.C.S. (Pre) 2012]
Ans. (c) Pluto
- At a meeting of the International Astronomical Union in 2006, Pluto was no longer considered a planet and was instead given the new classification of dwarf planet.
|
5. Which is the smallest planet of the solar system –
(a) Pluto
(b) Mars
(c) Venus
(d) Mercury
[U.P.P.C.S. (Pre) 1991]
Ans. (a) Pluto
- Before, Pluto was thought to be the smallest planet, with a size of 2370 Km or 1473 miles.
- However, now Mercury is seen as the tiniest planet in the solar system.
- The measurements for all eight planets are listed below :
- Mercury – 4,879 Km
- Venus – 12,104 Km
- Earth – 12,756 Km
- Mars – 6,792 Km
- Jupiter – 142,984 Km
- Saturn – 120,536 Km
- Uranus – 51,118 Km
- Neptune – 49,528 Km
|
6. The coldest planet in the solar system is –
(a) Neptune
(b) Jupiter
(c) Mars
(d) Saturn
[M.P.P.C.S. (Pre) 2014]
Ans. (a) Neptune
- Neptune, which is the planet the furthest away from the Sun, is the coldest in our solar system.
- Its surface temperature is a freezing -200 degrees Celsius and its atmosphere is made up of Hydrogen, Helium, and Methane.
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7. Which of the following planets is the farthest planet of the solar system –
(a) Neptune
(b) Pluto
(c) Sometimes Neptune and sometimes Pluto
(d) Mars
[I.A.S. (Pre) 2002, I.A.S. (Pre) 2005]
Ans. (c) Sometimes Neptune and sometimes Pluto
- Pluto is usually thought of as the planet that is the farthest away from the Sun.
- Its orbit is inside Neptune’s orbit, so sometimes Neptune is the planet that is farthest from the Sun.
- From 1979 to 1999, Neptune was the farthest planet, but on February 11th, 1999, Pluto took its place for the next 228 years.
- In 2006, Pluto was declared a dwarf planet, so now Neptune is the correct answer for the question of which planet is farthest from the Sun.
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8. Although Pluto is the farthest planet, its orbital path is excessively elliptical and crosses other planets’ orbital paths, resulting in the period starting from 1979 for 20 years Pluto is not the farthest planet, which planet is the farthest planet-
(a) Jupiter
(b) Saturn
(c) Uranus
(d) Neptune
[I.A.S. (Pre) 1993]
Ans. (d) Neptune
- Neptune is the planet that is the farthest from the Sun in our Solar System.
- But, Pluto’s orbit is different than other planets and it goes closer to the Sun than Neptune for 20 years out of its 249-year orbit.
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9. Nix and Hydra are the moons of –
(a) Pluto
(b) Venus
(c) Jupiter
(d) Mercury
[U.P.U.D.A./L.D.A .(Spl) (Mains) 2010]
Ans. (a) Pluto
- Pluto is a small planet in our Solar System and it has five moons.
- The names of these moons, from closest to Pluto to farthest, are Charon, Styx, Nix, Kerberos and Hydra, Charon is the largest.
- As of now, we know of 79 moons around Jupiter, but we don’t know if Venus or Mercury have any moons.
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XI. The Moon
1. When did man first land on the Moon?
(a) 1953
(b) 1963
(c) 1971
(d) 1969
[M.P.P.C.S. (Pre) 1995]
Ans. (d) 1969
- On July 20th, 1969, mankind took its first steps on the Moon.
- The Apollo-11 mission included three astronauts:
- Neil Armstrong
- Michael Collins
- Buzz Aldrin
- Armstrong and Aldrin were the only two to walk on the Moon’s surface.
- The Apollo-11 mission started from Florida, USA on July 16th and landed on the Moon’s ‘Sea of Tranquility’ on 20th July.
- On the 21st, the mission began its return to Earth and finally landed in the Pacific Ocean on the 24th.
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2. The “Sea of Tranquility” lies on –
(a) Earth
(b) Sun
(c) Jupiter
(d) Moon
[M.P.P.C.S. (Pre) 1995]
Ans. (d) Moon
- The dark area visible from Earth on the Moon is called Lunar Mare or the “Sea of Tranquility”.
- This is a large area where the Apollo 11 spacecraft landed in 1969.
- Neil Armstrong was the first person to walk on the Moon’s surface, followed by Edwin Aldrin.
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3. Assertion (A): The same face of the Moon always faces the Earth
Reason (R): The Moon completes one rotation around its own axis in 23 and half days which is about the same time that it takes to orbit the Earth.
(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A).
(c) (A) is true, but (R) is false.
(d) (A) is false, but (R) is true.
[I.A.S. (Pre) 2005]
Ans. (c) (A) is true, but (R) is false.
- The Moon’s orbit around the Earth is oval and slanted, so we can only see 59% of it.
- The Moon takes 27 days, 7 hours, and 43 minutes to spin on its own axis, which is the same amount of time it takes to orbit the Earth.
- This is why we always see the same side of the Moon.
- Therefore, statement A is true, but the reason for it (R) is not.
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4. Consider the following statements and answer the question with the help of codes given below :
Assertion (A): Only one side of the moon’s surface is visible from the earth.
Reason(R): The period of rotation of the moon on its axis is equal to the period of its revolution around the earth.
Code :
(a) Both (A) and (R) are true, and (R) is the correct explanation of (A)
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A)
(c) (A) is true, but (R) is false
(d) (A) is false, but (R) is true
[U.P.P.C.S. (Pre) 2006]
Ans. (a) Both (A) and (R) are true, and (R) is the correct explanation of (A)
- We can only see one side of the Moon from Earth because its orbit is elliptical and tilted.
- The Moon spins and moves around the Earth in 27 days, 7 hours and 43 minutes.
- This means that reason “R” is true.
- The Moon’s mass is unevenly distributed, so the Earth’s gravity pulls one side of the Moon closer to it.
- This proves that reason “R” explains statement “A” correctly.
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5. On the surface of the moon, two persons cannot listen to each other as –
(a) Their ears stops working at the Moon
(b) There is no atmosphere on the Moon
(c) They wear special types of space suits on the Moon
(d) Sound travels very slow on the Moon
[U.P.P.C.S. (Pre) 2003]
Ans. (b) There is no atmosphere on the Moon
- Sound waves need something to travel through to be heard, and the atmosphere is that something.
- Since there is no atmosphere on the Moon, two people cannot talk to each other there.
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6. When does a Lunar eclipse take place?
(a) When the moon comes between the sun and the earth
(b) When the earth comes between the sun and the moon
(c) When the sun comes between the earth and the moon
(d) None of these
[M.P.P.C.S. (Pre) 1994]
Ans. (b) When the earth comes between the sun and the moon
- When the Earth is between the Moon and the Sun, the Moon is blocked from the Sun’s light and appears dark.
- The type and length of the Lunar eclipse is determined by the Moon’s position and its orbit.
- Lunar eclipses only happen during a full moon.
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7. Lunar Eclipse is caused when –
(a) Moon comes in between Earth and Sun
(b) Earth comes between Sun and Moon
(c) Sun comes between Earth and Moon
(d) Sun and Moon coincide
[Uttarakhand Lower Sub. (Pre) 2010]
Ans. (b) Earth comes between Sun and Moon
- When the Earth moves between the Moon and the Sun, the Moon is blocked from the light coming from the Sun and becomes dark.
- The type and length of the Lunar eclipse depend on the Moon’s position and its path around Earth.
- A Lunar eclipse can only happen when the Moon is full.
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8. In which situation lunar eclipse occurs?
(a) Half Moon
(b) New Moon
(c) Full Moon
(d) None of these
[M.P.P.C.S. (Pre) 1992]
Ans. (c) Full Moon
- When the Earth is in between the Moon and Sun, the Moon is blocked from the Sun’s light and goes dark.
- How long the Lunar eclipse lasts and what type of eclipse it is depends on where the Moon is in its orbit.
- A Lunar eclipse only happens during a full moon.
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9. The main condition responsible for greater brightness of the moon on the full moon day of 22nd Dec. 99′ was :
(a) Aphelion
(b) Perihelion
(c) Apogee
(d) Perigee
[R.A.S./R.T.S.(Pre) 1999]
Ans. (d) Perigee
- The moon was very bright on December 22nd, 1999 because it was at its closest point to Earth, known as perigee.
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10. When the moon size is half of the full moon, the angle between the Sun, the Earth and the Moon is –
(a) 45o
(b) 90o
(c) 180o
(d) 270o
[U.P.P.C.S. (Pre) 2005]
Ans. (b) 900
- When the Moon is half full, the Sun, Earth, and Moon make a 90-degree angle.
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11. Choose the odd one –
(a) Mars
(b) Mercury
(c) Moon
(d) Earth
[Chhattisgarh P.C.S. (Pre) 2005]
Ans. (c) Moon
- Mars, Mercury, and Earth are all planets that revolve around the Sun, while the Moon is a satellite that orbits the Earth.
- The Moon belongs to a different category than the other three.
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12. Which of the following is not a planet?
(a) Moon
(b) Earth
(c) Mars
(d) Mercury
[Uttarakhand Lower Sub. (Pre) 2010]
Ans. (a) Moon
- The planets Mars, Mercury and Earth are all different from the Moon, which is a satellite of Earth.
- All three planets go around the Sun, while the Moon goes around the Earth.
- So, the Moon is a different type of object.
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13. Match the following –
(A) Planet (1) Moon
(B) Satellite (2) Uranus
(C) Comet (3) Mariner
(D) Artificial spacecraft (4) Halley
Code :
(a) A-2 B-1 C-4 D-3
(b) A-1 B-2 C-3 D-4
(c) A-4 B-3 C-1 D-2
(d) A-2 B-1 C-3 D-4
[U.P.P.C.S. (Pre) 1992]
Ans. (a) A-2 B-1 C-4 D-3
- The correct match is –
| Planet |
Uranus |
| Satellite |
Moon |
| Comet |
Halley |
| Artificial Spacecraft |
Mariner |
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14. The ‘blue moon’ phenomenon occurs when –
(a) Two full moons occur in the same month
(b) Four full moons appear in two consecutive months of the same calendar year
(c) Two full moons appear in the same month, thrice in a calendar
(d) None of the above
[U.P.P.C.S. (Mains) 2009, U.P.P.C.S. (Mains) 2007]
Ans. (a) Two full moons occur in the same month
- A blue moon happens when there is an extra full moon within a certain time period.
- A full moon usually comes around every 29.5 days, but after about 2.7154 years, an extra 29.5 days gets added to the calendar, creating an extra full moon.
- This is known as a blue moon.
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15. When any object is taken from the Earth to the Moon –
(a) Its weight increases
(b) Its weight decrease
(c) There is no change in its weight
(d) It becomes totally weightless
[U.P.P.C.S. (Pre) 2006]
Ans. (b) Its weight decrease
- The amount of force an object has due to gravity is determined by multiplying its mass by the gravity of the planet it’s on.
- The gravity on the moon is much less than that of Earth, so if an object is taken to the moon it will weigh much less than it does on Earth.
- Formula: Weight of Object = Mass × gravitational acceleration.
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16. The distance of the Moon from the Earth is –
(a) 364 thousand km
(b) 300 thousand km
(c) 446 thousand km
(d) 350 thousand km
[U.P. Lower Sub. (Pre) 2008]
Ans. (a) 364 thousand km
- The Moon is usually about 384,400 kilometers away from Earth.
- Out of the options given, the one closest to this number is 364,000 kilometers.
- The closest the Moon can get to Earth is 363,300 kilometers, and the furthest it can be is 405,500 kilometers.
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17. A country by sending its ‘SELENE’ (Selenological and Engineering Explorer) in the orbit of the Moon became the first country in Asia. The country which achieved this fame is –
(a) Japan
(b) China
(c) India
(d) Pakistan
[U.P.P.C.S. (Pre) 2009]
Ans. (a) Japan
- SELENE, also known as ‘Kaguya’, was a spacecraft sent to the Moon by Japan in 2007.
- It went around the Moon for 1 year and 8 months and then it crashed into the surface of the Moon, landing at Gill crater.
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XII. The Asteroids
1. The group of small pieces of rock revolving around the sun between the orbits of Mars and Jupiter are called:
(a) Meteors
(b) Comets
(c) Metroid
(d) Asteroids
[I.A.S. (Pre) 1997]
Ans. (d) Asteroids
- A bunch of tiny rocks that go around the Sun between Mars and Jupiter are known as asteroids.
- They come in different sizes, with some having a diameter of 1000 km.
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2. Consider the following statements regarding asteroids :
1. Asteroids are rocky debris of varying sizes orbiting the sun
2. Most of the asteroids are small but some have diameter as large and 1000 km
3. The orbit of asteroids lies between the orbits of Jupiter and Saturn
Of these statements :
(a) 1, 2, and 3 are correct
(b) 2 and 3 are correct
(c) 1 and 2 are correct
(d) 1 and 3 are correct
[I.A.S. (Pre) 1998]
Ans. (c) 1 and 2 are correct
- Asteroids are tiny rocks that orbit the Sun between Mars and Jupiter.
- They come in different sizes, some as large as 1000 km.
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3. The Asteroids are small celestial bodies in the solar system which are found between the planets
(a) Mercury and Venus
(b) Mars and Jupiter
(c) Jupiter and Saturn
(d) Neptune and Saturn
[U.P.P.C.S. (Pre) 2008]
Ans. (b) Mars and Jupiter
- Asteroids are the small pieces of rock that orbit the Sun between Mars and Jupiter.
- They can be different sizes, with some reaching up to 1000 km in diameter.
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4. What is the difference between asteroids and comets?
1. Asteroids are small rocky planetoids, while comets are formed of frozen gases held together by rocky and metallic material.
2. Asteroids are found mostly between the orbits of Jupiter and Mars, while comets are found mostly between Venus and Mercury.
3. Comets show a perceptible glowing tail, while asteroids do not.
Which of the statements given above is/are correct?
(a) 1 and 2
(b) 1 and 3
(c) 3 only
(d) 1, 2 and 3
[I.A.S. (Pre) 2011]
Ans. (b) 1, 2 and 3
- Asteroids are made up of mainly metal and rocks, while comets are mostly ice, dust, and rocks.
- Asteroids are closer to the sun, while comets come from the Kuiper Belt and Oort cloud, which are farther away.
- When comets get close to the sun, they form a tail, but asteroids usually stay the same.
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XIII. The Comets and Meteors
1. The tail of a comet is directed away from the Sun, because–
(a) As the Comet rotates around the Sun, the lighter mass of Comet is pushed away due to centrifugal force alone.
(b) As the Comet rotates, the lighter mass of the Comet is attracted by some stars situated in the direction of its tail.
(c) The radiation emitted by the Sun exerts a radial pressure on the comet throwing its tail away from the Sun.
(d) The Tail of the Comet always exists in the same orientation.
[I.A.S. (Pre) 1997]
Ans. (c) The radiation emitted by the Sun exerts a radial pressure on the comet throwing its tail away from the Sun.
- Comets in the outer solar system are very hard to spot from Earth because they are so small.
- When comets come closer to the inner solar system, the material inside them heats up and vaporizes, creating a cloud of gas and dust around the comet called a Coma.
- The radiation from the sun pushes this Coma away which then forms a long tail pointing away from the sun.
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2. Hale-Bopp is the name of a-
(a) Comet
(b) Cartoon Character
(c) International Company
(d) Toy
[M.P.P.C.S. (Pre) 1997]
Ans. (a) Comet
- Hale-Bopp is a special type of comet that was found in 1995.
- It was seen close to Jupiter’s orbit on July 23rd.
- It was named after the two astronomers, Alan Hale and Thomas Bopp, who discovered it.
- It was 1000 times brighter than Halley’s Comet, even though they were at similar distances.
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3. With which planet comet Shoemaker-Levy collided –
(a) Pluto
(b) Mars
(c) Jupiter
(d) Saturn
[I.A.S. (Pre) 1995]
Ans. (c) Jupiter
- In 1993, Carolyn Shoemaker and David Levy spotted Comet Shoemaker-Levy-9 in their telescope.
- Then in July of 1994, it crashed into the huge planet Jupiter, but nothing was damaged.
- It was the first time that people on Earth had seen a collision like this between two things in our solar system.
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4. Meteor is a –
(a) Fast-moving star
(b) A piece of matter which has entered the earth’s atmosphere from outer space
(c) Part of the stellar system
(d) Tailles Comet
[I.A.S. (Pre) 1995]
Ans. (b) A piece of matter which has entered the earth’s atmosphere from outer space
- A meteor is a bright streak of light in the sky commonly referred to as a shooting star or a falling star.
- However, it is not actually a star but instead a small piece of rocks and minerals.
- When it enters Earth’s atmosphere at a very high speed, it begins to glow due to the heat created by air friction.
- Most meteors burn up before reaching the ground.
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