Class 11 Geography Important Chapter 2 Origin and Evolution of the Earth

Class 11 Geography Important Chapter 2 Origin and Evolution of the Earth Solutions English Medium As Per AHSEC New Syllabus to each chapter is provided in the list so that you can easily browse through different chapters ASSEB Class 11 Geography Important Solutions and select need one. AHSEC Class 11 Elective Geography Additional Notes English Medium Download PDF. HS 1st Year Finance Important Solutions in English.

Class 11 Geography Important Chapter 2 Origin and Evolution of the Earth

Also, you can read the NCERT book online in these sections Solutions by Expert Teachers as per Central Board of Secondary Education (CBSE) Book guidelines. ASSEB Class 11 Elective Geography Additional Question Answer are part of All Subject Solutions. Here we have given HS 1st Year Elective Geography Important Notes in English for All Chapters, You can practice these here.

Origin and Evolution of the Earth

Chapter: 2

SECOND UNIT : OUR EARTH

IMPORTANT QUESTION AND ANSWER

Answer The Following Questions:

1. What is the central part of the Solar System?

Ans: The central part of the Solar System is the Sun.

2. How far is the Earth located from the Sun?

Ans: The Earth is located about 149.76 million kilometres away from the Sun.

3. Which is the largest planet in the Solar System?

Ans: The largest planet in the Solar System is Jupiter.

4. Which is the smallest planet in the Solar System?

Ans: The smallest planet in the Solar System is Mercury.

5. What is the approximate diameter of the Solar System in crore kilometres?

Ans: The approximate diameter of the Solar System is 1,179 crore kilometres.

6. What are called inner planets?

Ans: Mercury, Venus, Earth, and Mars are located within 250 million kilometres from the Sun. Hence, they are called inner planets.

7. In which year did the physicist Edwin Hubble observe the light rays coming from certain galaxies of the Universe?

Ans: In 1929, physicist Edwin Hubble observed the light rays coming from certain galaxies of the Universe.

8. Through how many main stages has the atmosphere evolved to reach its present state?

Ans: The atmosphere is believed to have evolved through three main stages to reach its present condition.

9. In which year did the International Astronomical Union declare that Pluto is not a full-fledged planet?

Ans: In 2008, the International Astronomical Union declared that Pluto is not a full-fledged planet.

10. What is the “Great Contraction”?

Ans: According to Hubble, in the early stage of the Universe, all matter existed in an extremely dense and hot state within a single primordial mass. This highly compressed state of the Universe is called the Great Contraction.

Long Question & Answer:

1. Discuss the traditional theories regarding the origin of the Earth.

Ans: The oldest and most popular traditional theory regarding the origin of the Earth is the Nebular Hypothesis. This theory, proposed jointly by German philosopher Immanuel Kant and mathematician Laplace, states that in the early stage, the rotating Sun threw off rings of matter due to centrifugal force. Each of these rings, under the influence of gravity, began to revolve around the Sun and eventually condensed into spherical bodies forming planets.

Another theory is the Tidal Hypothesis proposed by Chamberlin and Moulton, later developed by Jeans and Jeffreys. According to this theory, a massive star once passed close to the Sun, and due to its gravitational pull, a huge portion of the Sun’s gaseous matter was pulled out, forming a long filament-like mass. This mass later broke into several smaller fragments, which cooled and condensed into planets, including Earth, revolving around the Sun.

2. What is the Solar System? Discuss its structure and components.

Ans: The Solar System is a vast structure centred around the Sun, which includes the Sun, eight planets, numerous satellites, comets, asteroids, dust particles, gases, and other celestial bodies.

Earlier, people believed that the Earth was the centre of the Universe and that all celestial bodies revolved around it. However, Galileo, using a telescope, disproved this belief and established that the Sun is a star around which many planets, including the Earth, revolve.

The Sun, a gaseous star composed mainly of hydrogen and helium, lies at the centre of the Solar System. The eight planets in order from the Sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The four planets nearest the Sun — Mercury to Mars — are called terrestrial planets, as they are rocky, dense, and located close to the Sun. The outer planets — Jupiter to Neptune — are called gas giants, as they consist mainly of hydrogen and helium and have low density.

The Earth and other planets also have satellites. For example, the Earth has one natural satellite — the Moon, whereas Jupiter has more than 60 satellites. The Solar System also contains comets, which revolve around the Sun in long elliptical orbits and develop tails when near the Sun, and asteroids, found between Mars and Jupiter, which are small rocky bodies.