NCERT Solutions for Class 6 Social Science Geography Chapter 3 Motions of the Earth

 

NCERT Solutions for Class 6 Social Science Geography Chapter 3 Motions of the Earth

1. Answer the following questions briefly.

(a) What is the angle of inclination of the earth’s axis with its orbital plane?

👉 (a) The angle of inclination of the earth’s axis with its orbital plane is 66 1/2.

(b) Define rotation and revolution.

👉 (b) The movement of the earth on its axis is known as rotation.
‘ Revolution. The movement of the earth around the sun in a fixed path or orbit is known as revolution.

(c) What is a leap year?

👉 (c) The year in which February is of 29 days instead of 28 days is called a leap year. Thus a leap year is of 366 days instead of 365 days.

(d) Differentiate between the summer solstice and winter solstice.

(d) Difference between the summer solstice and winter solstice

Summer Solstice	Winter Solstice
1. Summer solstice experiences the longest day and shortest night of the year.	1. Winter solstice experiences the shortest day and longest night of the year.
2. Every year on June 21st summer solstice happens.	2. Every year in the month of December winter solstice happens, dates may vary.

(e) What is an equinox?

👉 (e) Equinox is the position of the Earth on 21st March and 23rd September. Both the hemispheres experience equal days and nights.

• On 21st March in the Northern hemisphere, this position is the spring equinox. Autumn equinox is in the Southern hemisphere.
• In the Northern hemisphere on 23rd September the position of the Earth is Autumn equinox and in the Southern hemisphere, it is the Spring equinox.

(f) Why does the Southern Hemisphere experience winter and summer solstice in different times than that of the Northern Hemisphere?

👉 (f) The Southern hemisphere experiences winter and summer solstice in different times than, that of the Northern hemisphere because of the following reasons:

• The southern hemisphere is tilted towards the Sun on 22nd December, hence summer solstice is there in the Southern hemisphere. At that time winter solstice is in the Northern hemisphere when it is away from the Sun.
• On the contrary, on 21 June the Northern hemisphere is tilted towards the Sun.
  Hence summer solstice is in the Northern hemisphere and winter solstice is in the Southern hemisphere.

(g) Why do the poles experience about six months’ day and six months’ night?

👉 (g) The poles experience six months’ day and six months’ night because of the following reasons:

• When the Northern hemisphere is tilted towards the Sun, the North Pole remains in the light for the whole of the day (24 hours). This position remains for six months (from 21st March to 23rd September).
• On the contrary in the Southern hemisphere, the South Pole does not get light during these six months. Hence it experiences night for six months (from 23rd September to 21st March).
• When the Southern hemisphere is tilted towards the sun, the South Pole remains in light for 24 hours for six months from 23rd September to 21st March. The reverse is the conditions at the North Pole-six months’ night.

2. Tick the correct answer.

(a) The movement of the earth around the sun is known as
(i) Rotation (ii) Revolution (iii) Inclination.

(b) Direct rays of the sun fall on the equator on
(i) 21 March (ii) 21 June (iii) 22 December.

(c) Christmas is celebrated in summer in
(i) Japan   (ii)India   (iii)Australia

(d) The cycle of the seasons is caused due to
(i) Rotation   (ii)Revolution  (iii)Gravitation

Fill in the blanks.

1. A leap year has ………… a number of days.
2. The daily motion of the earth is ……… ……
3. The earth travels around the sun in…………….
4. The sun’s rays fall vertically on the Tropic of…………….. on 21st June.
5. Days are shorter during …………

Answer:

1. 366
2. rotation
3. elliptical
4. cancer
5. winter

I. Multiple Choice Questions

Choose the correct option to complete the sentences given below:

(i) The axis of the earth is a/an……………..
(a) imaginary line                              (b) straight line
(c) curved line                                   (d) real line.

(ii) The earth receives light from the ……………
(a) Moon                                          (b) Stars
(c) Meteors                                        (d) Sun.

(iii) The time taken by the earth to complete one rotation around its axis is…………………
(a) 24 hours                                        (b) 12 hours
(c) 36 hours                                       (d) 18 hours.

(iv) The earth completes one revolution in ……………
(a) 366 days                                        (b) 370 days
(c) 365 1/4 days                                (d) 366 1/4 days.

(v) It is spring in the Northern Hemisphere and autumn in the Southern Hemisphere on ………………………….
(a) 23rd September                          (b) 21st March
(c) 22nd December                          (d) 21st June.

Answer: (i)—(a), (ii)—(d), (iii)—(a), (iv)—(c), (v)—(b)

III. True/False
Stale whether these sentences are true (T) or false (F).

1. The axis of the earth makes an angle of 23V& with its orbital plane.
2. Every five years, February is of 29 days instead of 28 days.
3. Season changes due to the change in the position of the earth around the sun.
4. When there is summer in the Northern Hemisphere, it is spring in the Southern Hemisphere.
5. Life is not possible in extreme conditions.

Answer:

1. False
2. False
3. True
4. False
5. True.

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