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

NCERT TEXTBOOK EXERCISE

Question 1. Answer the following questions briefly.
(a) What is the angle of inclination of the earth’s axis with its orbital plane?
(b) Define rotation and revolution.
(c) What is a leap year?
(d) Differentiate between the Summer and Winter Solstice.
(e) What is an equinox?
(f) Why does the Southern Hemisphere experience Winter and Summer Solstice in different times than that of the Northern Hemisphere?
(g) Why do the poles experience about six months day and six months night?
Answer:
(a) The earth remains tilted to one side while it revolves around the earth at an angle of 66.
(b) 1. Rotation: The movement/motion of the earth on its axis in 24 hours is defined as rotation.
2. Revolution: The movement/motion of the Earth around the Sun in its orbit in 36514 days is called revolution.
(c) It is a year when the month of February has 29 days instead of 28 days. Every fourth year is a leap year.
(d) Difference between Summer and Winter Solstice

Summer Solstice	Winter Solstice
1. Summer solstice occurs on 22nd June in 1 Northern hemisphere.	1. Winter solstice occurs on 22nd December in Northern hemisphere.
2. The whole Northern hemisphere experiences more heat and light.	2. Northern hemisphere experiences less heat and light.
3. It is summer in the Northern hemisphere.	3. It is winter in the Northern hemisphere.
4. Days are longer, nights are shorter.	4. Days are shorter, nights are longer.
5. Reverse conditions prevail in the Southern hemisphere.	5. Reverse conditions prevail in the Southern hemisphere.

(e) On 21st March and September 23rd, direct rays of the sun fall on the equator. At this position, neither of the poles is tilted towards the sun. Therefore, the entire earth experiences equal days and equal nights. This phenomenon is called an equinox.
(f) The seasons in Southern Hemisphere and Northern Hemisphere are exactly the opposite.
(g) When the rays of the sun fall directly on the Tropic of Cancer (21st June), the areas near the South Pole receive less heat. The North Pole is inclined towards the sun and places beyond the Arctic circle experience continuous daylight. At this time, the Southern Hemisphere has the opposite season. The nights are long and areas beyond the Antarctic circle get continuous nights. The reverse will happen on 22nd December.

Question 2. Tick the correct answers.
(а) 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) Cycle of the seasons is caused due to
(i) Rotation
(ii) Revolution
(iii) Gravitation

Answer:
(a) → (ii) Revolution
(b) → (i) 21 March
(c) → (iii) Australia
(d) → (ii) Revolution

Question 3. 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 ……….. orbit.
4. The sun’s rays fall vertically on the Tropic of ………… on 21st June.
5. Days are shorter during …………. season.
Answer:
1. 366
2. Rotation
3. Elliptical
4. Cancer
5. Winter

INTEXT QUESTIONS

Question 1. What would happen if the Earth did not rotate?
Answer: If the earth did not rotate,
1. The portion before the sun would have remained the same and continued to experience day regularly.
2. On the other hand, the portion of the Earth away from the sun would have experienced night continuously.
3. Life would have not been possible on the Earth in such a situation.

Question 2. Do you know in Australia Christmas is celebrated in the summer season?
Answer: Yes, we know that in Australia Christmas is celebrated in the summer season, i.e., 25th December when there is summer in Australia (the Southern Hemisphere).