Question

I. Short answer questions: 1. What is the earth's mean temperature? (1) 2. What is rotation? (1) 3. Which line of latitude is called the “Great Circle”? (1) 4. Which line is known as Prime meridian? (1) 5. Name the two motions of the earth? (1) II. Structured question: 1. a) Define Revolution? (1) b) Describe the characteristics of Rotation? (2) c) What is meant by Equinox? (2) 2. a) State the main five lines of latitudes? (1) b) Write any two characteristics of a Great circle? (2) c) It is 5:30pm in India when the Prime minister’s radio broadcast made from Montreal in Canada was heard. What must have been the time in Montreal? (2) 3. a) Why is earth called a watery planet? (1) b) Give any two features that make the earth a unique planet? (2) c) Briefly describe the shape of the earth? (2)

Answer 1

1. 15°C

2. The action of rotating about an axis or centre is called rotation.

3. The Equator is called the “Great Circle”.

4. Greenwich Meridian is called the 'Prime Meridian' or the 0° longitude.

5. Rotation and Revolution are two motions of Earth.

1. A forcible overthrow of a government or social order, in favour of a new system is called Revolution.

2. The Earth's axis of rotation is at a constant tilt with respect to its orbit around the Sun, resulting in the change of seasons. The physical characteristics of the Earth include its size and composition. The Earth also has gravity and magnetic force fields.

3. An equinox is a point in the year when daytime and nighttime are exactly the same length, 12 hours each. Equinoxes occur twice a year, usually on March 20 and Sept. 22, when the Earth is tilted neither toward nor away from the sun.

4. Equator , Tropic of cancer , Tropic of capricorn , Arctic circle , Antarctic circle are five main latitudes.

5.  A great circle has the same circumference, or outer boundary, and the same center point as its sphere. The geometry of spheres is useful for mapping the Earth and other planets. The Earth is not a perfect sphere, but it maintains the general shape. All the meridians on Earth are great circles.

6. 7:04 am

7. 75% of Earth's surface is covered by water in both liquid and frozen state. So, the Earth is also called “watery planet”. ..

8.

1. It is neither too hot nor too cold.
2. It had atmosphere surrounding it.

9. oblate spheroid

Since the Earth is flattened at the poles and bulges at the Equator, geodesy represents the figure of the Earth as an oblate spheroid. The oblate spheroid, or oblate ellipsoid, is an ellipsoid of revolution obtained by rotating an ellipse about its shorter axis.