Content:
3.1 Book PDF
3.2 Exercise Questions with Answers
3.1 Book PDF:3.1 Book PDF
3.2 Exercise Questions with Answers
Download chapters 3 of Motions of the Earth in PDF file from the links given below. Solutions to these chapters with important extra questions are also available on the below page.
3.2 Exercise Questions with Answers:
Answer the following questions briefly.
Q. 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 is 231⁄2°. The axis forms an angle of 661⁄2° with its orbital plane.
Q. Define rotation and revolution.
A. Rotation: The movement of the earth on its own axis is called rotation. The earth takes 24 hours to complete one rotation. It causes day and night.
Revolution: The movement of the earth around the sun in a fixed orbit is called revolution. The earth takes 365 days and 6 hours to complete one revolution. It causes seasons.
Q. What is a leap year?
A. Leap Year: The year (every four years) with 366 days instead of 365 days is known as a leap year.
Q. Differentiate between Summer and Winter Solstice.
A. Summer solstice: It is the position of the earth when the Northern Hemisphere has the longest day and the shortest night. It occurs on the 21st of June. In the Southern Hemisphere, it is winter season at this time. The days are short and the nights are long.
Winter solstice: It is the position of the earth when Southern Hemisphere has long days and shorter nights. In the Northern Hemisphere, the days are short and the nights are long. It occurs on the 22nd of December.
Q. What is an equinox?
A. Equinoxes are days when direct rays of the sun fall on the equator. At this position neither of the poles is tilted towards the sun, so the whole earth experiences equal days and equal nights. It occurs on 21st March and 23rd September.
Q. Why does the Southern Hemisphere experience Winter and Summer Solstice at different times than that of the Northern Hemisphere.
A. Since it is winter in the Southern Hemisphere when it is summer in the Northern Hemisphere, therefore the position of the earth ‘which is called the Winter Solstice in one Hemisphere is the Summer Solstice in the other, and vice-versa.
Q. Why do the poles experience six months day and six months night?
A. The axis of the earth is tilted, due to which the sun continuously either shines or cannot be seen for a long time here. Although the earth rotates and day changes into night and night into day at other places, but the poles remain under the same stage for a much longer time due to the tilt.
Q. 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 is 231⁄2°. The axis forms an angle of 661⁄2° with its orbital plane.
Q. Define rotation and revolution.
A. Rotation: The movement of the earth on its own axis is called rotation. The earth takes 24 hours to complete one rotation. It causes day and night.
Revolution: The movement of the earth around the sun in a fixed orbit is called revolution. The earth takes 365 days and 6 hours to complete one revolution. It causes seasons.
Q. What is a leap year?
A. Leap Year: The year (every four years) with 366 days instead of 365 days is known as a leap year.
Q. Differentiate between Summer and Winter Solstice.
A. Summer solstice: It is the position of the earth when the Northern Hemisphere has the longest day and the shortest night. It occurs on the 21st of June. In the Southern Hemisphere, it is winter season at this time. The days are short and the nights are long.
Winter solstice: It is the position of the earth when Southern Hemisphere has long days and shorter nights. In the Northern Hemisphere, the days are short and the nights are long. It occurs on the 22nd of December.
Q. What is an equinox?
A. Equinoxes are days when direct rays of the sun fall on the equator. At this position neither of the poles is tilted towards the sun, so the whole earth experiences equal days and equal nights. It occurs on 21st March and 23rd September.
Q. Why does the Southern Hemisphere experience Winter and Summer Solstice at different times than that of the Northern Hemisphere.
A. Since it is winter in the Southern Hemisphere when it is summer in the Northern Hemisphere, therefore the position of the earth ‘which is called the Winter Solstice in one Hemisphere is the Summer Solstice in the other, and vice-versa.
Q. Why do the poles experience six months day and six months night?
A. The axis of the earth is tilted, due to which the sun continuously either shines or cannot be seen for a long time here. Although the earth rotates and day changes into night and night into day at other places, but the poles remain under the same stage for a much longer time due to the tilt.
Tick the correct answer :
Q. The movement of the earth around the sun is known as
Q. Direct rays of the sun fall on the equator on
Q. Christmas is celebrated in summer in
Q. Cycle of the seasons is caused due to
Q. The movement of the earth around the sun is known as
- (1) Rotation
- (2) Revolution
- (3) Inclination
Q. Direct rays of the sun fall on the equator on
- (1) 21st March
- (2) 21st June
- (3) 22nd December
Q. Christmas is celebrated in summer in
- (1) Japan
- (2) India
- (3) Australia
Q. Cycle of the seasons is caused due to
- (1) Rotation
- (2) Revolution
- (3) Gravitation
Fill in the blanks :
Q. A leap year has ______ number of days.
A. 366
Q. The daily motion of the earth is ______.
A. Rotation
Q. The earth travels around the sun in ______ orbit.
A. Elliptical
Q. The sun’s rays fall vertically on the Tropic of ______ on 21st June.
A. Cancer
Q. Days are shorter during ______ season.
A. winter
Q. A leap year has ______ number of days.
A. 366
Q. The daily motion of the earth is ______.
A. Rotation
Q. The earth travels around the sun in ______ orbit.
A. Elliptical
Q. The sun’s rays fall vertically on the Tropic of ______ on 21st June.
A. Cancer
Q. Days are shorter during ______ season.
A. winter
