## शनिवार, 22 जुलाई 2017

### Chapter 3 –MOTIONS OF THE EARTH

Class–VI GEOGRAPHY
Chapter 3 –MOTIONS OF THE EARTH
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 indifferent times than that of the Northern Hemisphere?
(g) Why do the Poles experience about six months day and six months night?
Answer :(a) The angle of inclination of the Earth’s axis with its orbital plane is 66$\frac{1}{2}{}^{\circ }$ .
(b) Rotation is the movement of the Earth on its axis.Revolution is the movement of the Earth around the Sun in a fixed path or orbit.
(c) Earth takes 365$\frac{1}{4}$ days to revolve around the Sun. However, for the sake ofconvenience, we consider a year as consisting of 365 days. The six hours ($\frac{1}{4}$th of 24hours) that are ignored make one day (24 hours) over a span of four years. Thissurplus day is added to the month of February. Thus, every fourth year, Februaryhas 29 days, and such a year (with 366 days) is known as a leap year.
(d)
 Summer Solstice Winter Solstice It is the position of the Earth when the rays of the Sun fall directly on the Tropic of Cancer. It is the position of the Earth when the rays of the Sun fall directly on the Tropic of Capricorn In this position, the North Pole is tilted towards the Sun. In this position, the North Pole is tilted away from the Sun. A larger portion of the Northern Hemisphere gets light from the Sun; hence, it is summer in the Northern Hemisphere. A larger portion of the SouthernHemisphere gets light from the Sun; hence, it is winter in the Northern Hemisphere. During this period in the Northern Hemisphere, days are longer than nights. During this period in the Northern Hemisphere, nights are longer than days.
(e) Equinox is the position of the Earth when the rays of the Sun fall directly on theEquator. At this position, neither of the Poles is tilted towards the Sun. As a result,the entire Earth has equal days and equal nights.
(f) When the North Pole is tilted towards the Sun, the Northern Hemisphereexperiences Summer Solstice. At this time, since the South Pole is tilted away fromthe Sun, the Southern Hemisphere experiences Winter Solstice.When the North Pole is tilted away from the Sun, the Northern Hemisphereexperiences Winter Solstice. At this time, since the South Pole is tilted towards theSun, the Southern Hemisphere experiences Summer Solstice.
(g) The Poles experience about six months of day and six months of night becauseof the tilt of the Earth on its axis. Because of this tilt, each Pole is tilted towards andaway from the Sun for about six months each.
When the North Pole is tilted towards the Sun, it experiences continuous daylight forsix months. It is night for the same time period at the South Pole. These conditionsare reversed when the South Pole is tilted towards the Sun.
Question 2: Tick the correct answers
(a) 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) June
(iii) 22 December
(c) Christmas is celebrated in summer in
(i) Japan
(ii) India
(iii) Australia
(d) Cycle of seasons is caused due to
(i) Rotation
(ii) Revolution
(iii) Gravitation
(a) The movement o 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 seasons is caused due to
(i) Rotation
(ii) Revolution
(iii) Gravitation
Question 3:
Fill in the blanks.
(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 21st June.
(e) Days are shorter during _________ season
(a) A leap year has 366 numbers of days.
(b) The daily motion of the Earth is rotational.
(c) The Earth travels around the Sun in a fixed elliptical orbit.
(d) The Sun’s rays fall vertically on the Tropic of Cancer on 21st June.
(e) Days are shorter during winter season.