Chapter 1 – Earth as a Planet

Earth as a Planet is an important chapter in WBBSE Class 9 Geography. Here, you will find Earth as a Planet questions and answers arranged clearly to help you revise quickly and prepare better for your exams.

Content Structure

1. Multiple choice questions and answers (MCQs)
2. Very short-type questions and answers
- 2A. Fill in the blanks
- 2B. True or false
- 2C. Match the following
- 2D. Single word questions and answers
3. Short-type questions and answers
4. Long-type questions and answers

1. Multiple choice questions and answers (MCQs)

1. “The Earth revolves around the Sun and rotates on its own axis” was first stated by—
(a) Galileo
(b) Newton
(c) Copernicus
(d) Aryabhatta

Ans: (d) Aryabhatta

2. The planet nearest to the Earth is—
(a) Mercury
(b) Jupiter
(c) Venus
(d) Mars

Ans: (c) Venus

3. “The Earth revolves around the Sun” was first stated by—
(a) Galileo
(b) Aryabhatta
(c) Copernicus
(d) Varahamihira

Ans: (c) Copernicus

4. The highest point on the surface of the Earth is—
(a) Mount Everest
(b) Pamir Plateau
(c) North Pole region
(d) Tibetan Plateau

Ans: (a) Mount Everest

5. An example of a dwarf planet is—
(a) Mercury
(b) Pluto
(c) Venus
(d) Earth

Ans: (b) Pluto

6. The Bedford Canal Experiment was carried out by—
(a) Foucault
(b) Galileo
(c) Wallace
(d) Torricelli

Ans: (c) Wallace

7. In 1797, Henry Cavendish determined the Earth’s—
(a) Weight
(b) Diameter
(c) Circumference
(d) Density

Ans: (d) Density

8. At present, the number of dwarf planets is—
(a) 4
(b) 3
(c) 6
(d) 5

Ans: (d) 5

9. At present, the number of planets in the solar system is—
(a) 7
(b) 8
(c) 5
(d) 3

Ans: (b) 8

10. The largest planet in the solar system is—
(a) Venus
(b) Mars
(c) Jupiter
(d) Mercury

Ans: (c) Jupiter

11. The deepest point of the Mariana Trench is about—
(a) 10,053 m
(b) 11,350 m
(c) 11,035 m
(d) 10,994 m

Ans: (c) 11,035 m

12. The Cayenne Islands are in—
(a) North America
(b) Australia
(c) Asia
(d) South America

Ans: (d) South America

13. The Sun is a—
(a) Planet
(b) Satellite
(c) Galaxy
(d) Star

Ans: (d) Star

14. The number of Jovian planets in the solar system is—
(a) 7
(b) 8
(c) 9
(d) 4

Ans: (d) 4

15. One satellite of Saturn is—
(a) Moon
(b) Phobos
(c) Titan
(d) Haumea

Ans: (c) Titan

16. “The Earth is round” was first stated by—
(a) Plato
(b) Strabo
(c) Pythagoras
(d) Aristotle

Ans: (c) Pythagoras

17. The word ‘geoid’ means—
(a) Perfect sphere
(b) Flattened
(c) Oblate spheroid
(d) Earth-like shape

Ans: (d) Earth-like shape

2. Very short-type questions and answers

2A. Fill in the blanks

1. The first person to calculate the circumference of the earth was _________. (Eratosthenes).
2. One stadia is equal to __________ metere. (157.5)
3. The earth is an __________ spheroid. (oblate)
4. Magellan started his expedition from the city of __________ in spain. (Seville)
5. The bedfort canal experiment proves that the earth is _________. (curved)
6. The earthe’s polar diameter is ____________ km. (12,714 km)
7. In the year _____________, lean richard conducted the pendulum experiment. (1672)
8. _______ first calculated the circumference of the earth. (Eratosthenes)
9. The temperature of Uranus and _____ always goes below the freezing point. (Neptune)
10. The earth equatorial diameter is ___________ than its polar diameter. (greater)
11. The person who first succeeded in estimating the volume of the earth was ____________. (Archimedes)
12. The actual shape of the earth is ____________ spheroid. (oblate)
13. The farthest planet from the sun is ___________. (Neptune)
14. Photograph taken from the space shows ________ shape of the earth. (spherical)
15. According to size the fifth planet of the solar system is ___________. (Earth)

2B. True or false

1. The moon does not have any light of its own. (True)
2. Artificial satellites are used to gather information for use by GPS. (True)
3. The main control system of GPS is in the united states of America. (True)
4. According to Eratosthenes the circumference of the earth is 2,50,000 stadia. (True)
5. The jupitar is the largest planet of the solar system. (True)
6. Life is not found only on the earth. (False)
7. The shape of the earth is ellipsoid. (True)
8. Mercury is the nearest planet of the sun. (True)
9. The stars do not have own light. (False)
10. Mars is the nearest planet to the earth. (False)
11. The moon is the only satellite of the earth. (True)

2C. Match the column

Column A	Column B
1. New Moore	A. Depositional plain
2. Bajada	B. Glacier
3. Barkhans	C. Island
4. Lambert	D. Crescent shaped dunes

Ans:

Column A	Column B
1. New Moore	C. Island
2. Bajada	A. Depositional plain
3. Barkhans	D. Crescent shaped dunes
4. Lambert	B. Glacier

2D. Single word questions and answers

1. What is oblate spheroid?
Ans: An oblate spheroid is a shape that is slightly flattened at the poles and bulged at the equator, like the Earth.

2. Write the name of the planets nearest and farthest from the earth.
Ans:
Nearest planet to the Earth – Venus
Farthest planet from the Earth – Neptune

3. What is horizon?
Ans: The horizon is the imaginary line where the sky appears to meet the Earth’s surface.

4. Why does the Moon appear bigger even though it is smaller than planets?
Ans: The Moon appears bigger because it is much closer to the Earth than other planets.

5. What is Geoid?
Ans: Geoid is the actual shape of the Earth, which is uneven due to mountains, valleys and oceans.

6. Where is located the Kuiper Belt and Oort Cloud?
Ans:
The Kuiper Belt is located beyond the orbit of Neptune.
The Oort Cloud lies far beyond the Kuiper Belt, surrounding the solar system.

7. What is GPS?
Ans: Global Positioning System is a satellite-based system used to find the exact location of a place on the Earth.

8. What is proved by the circumnavigators?
Ans: Circumnavigators proved that the Earth is round.

9. Mention three proofs of the round shape of the Earth.
Ans:
(i) Circumnavigation of the Earth
(ii) Circular shadow of Earth during lunar eclipse
(iii) Ships disappear hull first at sea

10. How much is the temperature of Mercury?
Ans:
Maximum temperature of Mercury – about 430°C
Minimum temperature of Mercury – about 180°C

11. What is the estimated mass of the earth?
Ans: The estimated mass of the earth is about 5.97 × 10²⁴ kilograms.

12. What is the average temperature of the Earth?
Ans: The average temperature of the Earth is about 15°C.

13. How much time does it take for the light of the sun to reach the earth?
Ans: Sunlight takes about 8 minutes and 20 seconds to reach the earth.

14. What is a comet?
Ans: A comet is a heavenly body made of ice and dust that revolves around the Sun in a highly elliptical orbit.

15. What is the area of the earth’s surface?
Ans: The total surface area of the earth is about 510 million square kilometres.

16. Name one Jovian planet.
Ans: Jupiter is a Jovian planet.

17. What is the only source of light in the solar system?
Ans: The Sun is the only source of light in the solar system.

18. What is the full form of GPS?
Ans: The full form of CPS is Global Positioning System.

19. Name two planets that do not have satellites.
Ans: Mercury and Venus are the two planets that do not have any satellites.

20. Which heavenly body is at the centre of the solar system?
Ans: The Sun is at the centre of the solar system.

21. Which heavenly body is the source of light to the solar system?
Ans: The Sun is the source of light to the solar system.

22. Which is the deepest point on the earth?
Ans: The Mariana Trench is the deepest point on the earth.

23. What is the minimum number of satellites required to operate GPS?
Ans: A minimum of four satellites is required to operate GPS.

24. What is the average temperature of the earth?
Ans: The average temperature of the earth is about 15°C.

25. Which planet is known as the Red Planet?
Ans: Mars is known as the Red Planet.

26. What is the full form of IAU?
Ans: The full form of IAU is International Astronomical Union.

27. Where was the General Assembly of the IAU held on August 24, 2006?
Ans: The General Assembly of the IAU was held in Prague, Czech Republic.

28. Who was the first person to use the word ‘geoid’?
Ans: Johann Benedict Listing was the first person to use the word geoid.

29. From where did GPS become operational?
Ans: GPS became operational from the United States of America.

30. In which direction does the earth rotate?
Ans: The earth rotates from west to east.

31. Where is the earth’s diameter the greatest?
Ans: The earth’s diameter is greatest at the equator.

32. What does the science of geodesy study?
Ans: Geodesy is the science that studies the shape, size, and gravitational field of the earth.

33. Where was the Bedford Level Experiment conducted?
Ans: The Bedford Level Experiment was conducted in Bedfordshire, England.

34. Which is the largest planet in the solar system?
Ans: Jupiter is the largest planet in the solar system.

35. From where do living things get the oxygen they need to live?
Ans: Living organisms get oxygen from the atmosphere.

3. Short-type questions and answers

1. Why is the earth called the blue planet?
Ans: The Earth is called the Blue Planet because about 71% of its surface is covered with water and when seen from space, the large water bodies make the Earth appear blue.

2. What is planet?
Ans: A planet is a non-luminous celestial body that moves around a star in a definite elliptical orbit. It does not have its own light but shines by reflecting the light of the star around which it moves.

3. What is geodesy?
Ans: Geodesy is the branch of science that studies the shape, size, structure and gravitational field of the Earth, which helps in understanding the actual shape of the Earth.

4. What is star?
Ans: A star is a heavenly body having its own light and heat, and the Sun is the nearest star to the Earth and the main source of heat and light for the solar system.

5. In which part of the world did GPS first come into use?
Ans: GPS first came into use in the United States of America, where it was developed mainly for military purposes and later made available for civilian use.

6. What information can be gathered from a GPS receiver?
Ans: A GPS receiver can provide information about the exact location, altitude, distance, direction and accurate time of a place on the Earth.

7. What is GPS?
Ans: GPS or Global Positioning System is a satellite-based navigation system that helps to determine the exact position, direction, distance and time of any place on the Earth.

8. Where is the kuiper belt located?
Ans: The Kuiper Belt is a belt-shaped zone of the solar system outside the orbit of Neptune, where many icy bodies and dwarf planets such as Pluto are found.

4. Long-type questions and answers

1. Why is the average distance between the earth and the sun not the same throughout the year?
Ans: The average distance between the Earth and the Sun does not remain the same throughout the year because the Earth revolves around the Sun in an elliptical orbit and not in a circular one. During its revolution, the Earth comes closer to the Sun at a position called perihelion and moves farther away from the Sun at a position called aphelion. Due to this change in position, the distance between the Earth and the Sun varies slightly at different times of the year.

2. How is the earth unique among all the other planets in the solar system?
Ans: The Earth is different from all the planets of the solar system because it is the only planet where life exists. The Earth has air for breathing, water for living organisms, and a suitable temperature which is neither too hot nor too cold. It also has soil on land which helps plants to grow because of these conditions, plants, animals and human beings can live on the Earth. These conditions are not found on any other planet of the solar system.

3. Why is the earth considered to be a planet of the solar system?
Ans: The Earth is considered to be a planet of the solar system because it fulfils all the necessary conditions of a planet. It revolves around the Sun in a fixed elliptical orbit and does not have its own light, but shines by reflecting the light of the Sun. The Earth has sufficient mass to maintain a nearly spherical shape and has cleared its orbital path of other bodies.

4. Curvature of the earth’s surface is lesser at the equator than at the pooles- Explain.
Ans: The curvature of the Earth’s surface is less at the equator than at the poles because of the rotation of the Earth. The rotation of the Earth produces centrifugal force, which is greatest at the equator and least at the poles. This force causes the equatorial region to bulge outward, increasing the diameter at the equator. As a result, the surface becomes flatter and less curved at the equator, while the polar regions remain more curved.

5. Why was pluto been classified as a dwarf planet?
Ans: Pluto was classified as a dwarf planet by the International Astronomical Union (IAU) in 2006 because it does not satisfy all the conditions required to be called a planet. Although Pluto revolves around the Sun and has enough mass to be nearly spherical in shape, it has not been able to clear its orbital path of other celestial bodies. Many icy objects of the Kuiper Belt move along with Pluto in its orbit. As Pluto does not fulfil this important condition, it has been placed in the category of a dwarf planet.