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Q1. Answer the following questions briefly.
(a) What is the angle of inclination of the earth’s axis with its orbital plane?
Ans: The earth is tilted at 66 ½0 on its orbital plane.
(b) Define rotation and revolution.
Ans: Rotation: Spinning of the earth on its own axis is called rotation.
Revolution: The earth move in a fixed orbit around the sun, this movement is called revolution. Our earth takes 365 ½ days to complete one revolution around the sun.
(c) What is a leap year?
Ans: The year, which has 366 days in it is called a leap year.
(d) Differentiate between the Summer and Winter Solstice.
Ans: Summer solstice: On 21 June, the Northern hemisphere is tilted towards the sun that makes the day longer in northern hemisphere while it is winter in southern hemisphere. This position of earth is called summer solstice.
Winter solstice: On 22 December, the southern hemisphere is tilted towards the sun that make the days longer in southern hemisphere while it is winter in the northern hemisphere. This position of earth is called winter solstice.
(e) What is an equinox?
Ans: On 21st March and 23rd September, the days and nights are equal on the earth. This position is called equinox.
(f) Why does the Southern Hemisphere experience Winter and Summer Solstice in different times than that of the Northern Hemisphere?
Ans: When the earth is tilted, towards southern hemisphere it experience summer at the same time northern hemisphere goes away from the sun and it experience winter and vice versa.
(g) Why do the poles experience about six months day and six months night?
Ans: The earth is tilted on its axis, which keep the poles away from the sun and vice versa, that is why poles experience about six months day and six months night.
Q2. Tick the correct answers.
(a) The movement of the earth around the sun is known as
(i) Rotation (ii) Revolution (iii) Inclination
Ans: (ii) Revolution
(b) Direct rays of the sun fall on the equator on
(i) 21 March (ii) 21 June (iii) 22 December
Ans: (i) 21 March
(c) Christmas is celebrated in summer in
(i) Japan (ii) India (iii) Australia
Ans: (iii) Australia
(d) Cycle of the seasons is caused due to
(i) Rotation (ii) Revolution (iii) Gravitation
Ans: (ii) Revolution
3. Fill in the blanks.
(a) A leap year has 366 number of days.
(b) The daily motion of the earth is Rotation.
(c) The earth travels around the sun in elliptical orbit.
(d) The sun’s rays fall vertically on the Tropic of Cancer on 21st June.
(e) Days are shorter during winter season.