NCERT Solutions for Class 6 Social science Chapter 3 Motions Of The Earth are provided here with simple step-by-step explanations. These solutions for Motions Of The Earth are extremely popular among class 6 students for Social science Motions Of The Earth Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the NCERT Book of class 6 Social science Chapter 3 are provided here for you for free. You will also love the ad-free experience on Meritnation’s NCERT Solutions. All NCERT Solutions for class 6 Social science are prepared by experts and are 100% accurate.

Page No 25:

Question A.1:

What do you mean by the inclination of the earth's axis?

Answer:

The tilted position of the Earth's axis is known as inclination of the Earth's axis. The Earth's rotation axis makes an angle of about 66.5° with the plane of its orbit around the Sun or about 23.5° from the perpendicular to the elliptical plane. This inclination is the reason we experience different seasons on the Earth.

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Question A.2:

What are the effects of the earth's rotation?

Answer:

The Earth rotates about its axis and it takes about 24 hours to complete one rotation. Some of the effects of the Earth's rotation are as follows:

  1. Rotation creates a diurnal cycle of light and darkness, i.e. day and night.
  2. Rotation causes tides, i.e. rise and fall of the sea level twice a day.
  3. Rotation causes sunrise in the east and sunset in the west.

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Question A.3:

Why does February have 29 days after every 4 years?

Answer:

The Earth revolves around the Sun in anticlockwise direction and it takes about 365 days and 6 hours to complete one revolution. However, for our convenience, these extra 6 hours are added every year for the next four years to create a total of 24 hours or one more day in February. This extra day in February comes after every four years and the year in which it occurs is known as the leap year; it has 366 days in total.

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Question A.4:

What are the effects of revolution?

Answer:

The Earth takes around 365 days and 6 hours to complete one revolution around the Sun. The effects of the Earth's revolution are as follows:
  1. Variation in the lengths of days and nights
  2. Slanting or vertical sunrays
  3. Occurrence of various seasons (spring, summer, autumn and winter) 
  4. Movement of the Sun between the Tropic of Cancer and the Tropic of Capricorn

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Question A.5:

Name the two factors responsible for the occurrence of seasons.

Answer:

The two factors responsible for the occurrence of seasons are as follows:
  1. The Earth rotates on its own axis and it is tilted at an angle of 23.5° with respect to its orbital plane; this causes the occurrence of seasons.
  2. The revolution of the Earth around the Sun, which requires 365 days and 6 hours, in an elliptical orbit also causes the change in seasons.

Page No 25:

Question B.1:

Rotation and revolution

Answer:

 

Rotation  Revolution
1. The Earth takes 24 hours to complete one rotation. The Earth takes around 365 days and 6 hours to complete one revolution around the Sun.
2. The Earth rotates on its axis.  The Earth revolves around the Sun in an elliptical orbit.
3. The rotation of the Earth causes day and night. The revolution of the Earth causes the occurrence of seasons.

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Question B.2:

Vertical rays of the sun and slanting rays of the sun

Answer:

Vertical Rays Slanting Rays
1. These are concentrated rays and carry more heat. These are not concentrated and carry less heat.
2. These rays spread over a very small area on the Earth These rays spread over a large area on the Earth.
3. The part of the Earth tilted towards the Sun receives vertical rays. The part of the Earth tilted away from the Sun receives slanting rays.

Page No 25:

Question C.1:

We have alternate days and nights.

Answer:

This is because the Earth rotates on its axis and completes one rotation in 24 hours. During this rotation, sunrays fall on half of the spinning Earth and this half of the Earth experiences day. The other darker side of the Earth experiences night during this time. With each spin, the Earth moves from darkness to light and vice versa. 

Page No 25:

Question C.2:

Days and nights are not equal in length.

Answer:

The variation in the lengths of days and nights occurs because the Earth revolves around the Sun, with its axis always inclined at an angle of 66.5°. This causes longer days and shorter nights in summer in the southern hemisphere. This variation between the lengths of  days and nights increases with increasing distance from the Equator to the poles.

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Question C.3:

21st June is the longest day in the Northern Hemisphere.

Answer:

On 21 June, the Northern Hemisphere is inclined towards the Sun. The rays of the Sun fall directly on the Tropic of Cancer, causing summer in the Northern Hemisphere and winter in the Southern Hemisphere. Because of this, we experience the longest day and the shortest night of the year on 21 June. 

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Question C.4:

On 21st March and 23rd September days and nights are equal all over the world.

Answer:

On 21 March and 23 September, the Sun shines vertically on the Equator; therefore, all places on the Earth experience equal days and equal nights. On 21 March, the Northern Hemisphere has spring, while the Southern Hemisphere has autumn. On 23 September, ​the Northern Hemisphere has autumn, while the Southern Hemisphere has spring.

Page No 25:

Question D.1:

The angle which the earth's axis makes with the plane of the earth's orbit is

a. 23½°
b. 60°
c. 66½°
d. 90°

Answer:

The correct answer is option (a).
 

Explanation: The Earth's axis is an imaginary line joining the North Pole and the South Pole. This axis is tilted at an angle of 23½° with respect to the plane of the Earth's orbit. This tilt is also known as the inclination of the Earth's axis.

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Question D.2:

The time of the day just before sunrise is known as

a. dusk
b. dawn
c. twilight
d. morning

Answer:

The correct answer is option (b).

Explanation: Dawn is the time just before sunrise. During this time, the sky starts getting filled with the Sun's glow and the rays of the Sun start piercing the darkness.

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Question D.3:

During summer the poles have continuous daylight for

a. 6 months
b. 3 months
c. 1 months
d. 2 months

Answer:

The correct answer is option (a).

Explanation: During summer, both the poles, i.e. the North and South Poles, experience continuous daylight for a period of six months; during winter, both the poles experience continuous darkness for a period of six months.

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Question D.4:

22nd December is the shortest day in the

a. Southern Hemisphere
b. regions near the poles
c. regions near the Equator
d. Northern Hemisphere

Answer:

The correct answer is option (d).
 

Explanation: On 22 December, the Northern Hemisphere turns away from the Sun and experiences the shortest day. On the contrary, at this time, the Southern Hemisphere inclines towards the Sun and therefore experiences the longest day. 

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Question E:

A B
Magellan
Summer Solstice
Spring Equinox
Rotation
Revolution
Causes deflection of winds
in Northern Hemisphere is on 21 March
causes seasons
proved that the earth is round
is the longest day

Answer:

 

A B
Magellan proved that the Earth is round
Summer solstice is the longest day
Spring equinox in the Northern hemisphere is on 21 March
Rotation causes deflection of winds
Revolution causes seasons

Explanation: 

1. In olden days, people used to think that the Earth is like a flat disc. But Magellan proved that the Earth is round.
2. During the summer solstice, the Northern Hemisphere witnesses its longest day of the year.
3. â€‹On 21 March every year in the Northern Hemisphere, the spring equinox happens when the length of the day and that of the night are equal.
4. The rotation of the Earth is responsible for the deflection of winds.
5. The revolution of the Earth around the Sun causes the change in seasons (summer, winter, spring etc.) on the Earth.

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Question F:

Draw neat and labelled diagrams to show the occurrence of day and night and the occurrence of seasons

Answer:

Occurrence of Day and Night




Occurrence of Seasons



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