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(a) What is the angle of inclination of the earth’s axis with its orbital plane?
Ans. The angle of inclination of the earth’s axis with its orbital plane is 66 ½º.
(b) Define rotation and revolution.
(c) What is a leap year?
Ans. Earth takes 365 days and 6 hours to complete a revolution. But, for the sake of convenience, we consider that a year consists of 365 days. The six hours that are ignored make one day (24 hours) over a period of four years. This one day is added to that year in the month of February. Therefore, after every four years February has 29 days and that year is known as leap year.
(d) Differentiate between the Summer and Winter Solstice.
(e) What is an equinox?
Ans. 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 whole earth experiences equal days and equal nights. This is called an equinox.
(f) Why does the Southern Hemisphere experience Winter and Summer Solstice at different times than that of the Northern Hemisphere?
The Southern Hemisphere experience Winter and Summer Solstice at different times than that of the Northern Hemisphere because:
(g) Why do the poles experience about six months day and six months night?
Ans. The Poles experience about six months of day and six months of night because of the tilt of the Earth on its axis. When the Northern hemisphere is tilted towards the Sun, the North Pole is inclined towards the sun, it experiences continuous daylight for six months. These conditions are reversed when the southern hemisphere is tilted towards the Sun.
(a) The movement of the earth around the sun is known as
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
Ans. (iii) Australia
(d) Cycle of the seasons is caused due to
Ans. (ii) Revolution
(a) A leap year has ____ number of days.
(b) The daily motion of the earth is _____.
(c) The earth travels around the sun in ____ orbit.
(d) The sun’s rays fall vertically on the Tropic of ___ on 21 st June.
(e) Days are shorter during ___ season.