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Std-7th, lesson no-8 How seasons occur – Part 2, Q.1 answer the following question, 1. what leads to the occurrence of seasons?, ans: it is the tilt of the axis that leads to occurrence of seasons change and divsersity on the earth . the living world on the earth is affected by the cycle of seasons, 2. what is the duration of the day on equinox ?, Ans: as the earth revolves around the sun the equator receives perpendicular rays on two days in a year. This condition occurs on 21st march and 23rd September, 3. why is the effect of the seasons not experienced in the equatorial region ?, Ans: seasons have been decided on the basis of the duration of sunlight, equinox and solstices. The equatorial region does not experience any change of seasons, hence the climate in that region does not change at all in the year, 4. Why is the sun visible for those 24 hours during dakshinayan in the region between the Antarctic Circle and the South Pole?, ans: 1.sunrays are never perpendicular on an of the parallels between tropic of cancer and the north pole or between tropic of Capricorn and the south pole ., 2. Similar situation prevails in the region between the Antarctic circle and the south pole in the period from 23rd September to 21st march. Note that on the equator, the duration of days and night is same throughout the year. i.e. 12 hours each, 5. Why are penguins not found at the North Pole?, ans: penguins are native to the southern pole and not found at the northern pole, Q.2 complete statement using correct option, 1. The apparent movement of the sun mean it appears that the sun moves to the north or south in a year, 2. If the axis of the earth were not tilted different parallels on the earth would have experienced the same climate throughout the year, 3. 21st June and 22december are solstices days , that is the sun starts its southwards journey from tropic of cancer on 21st June and northward journey from tropic of Capricorn on 22nd December, 4.the revolution of the earth around the sun and tilt of the axis of the earth together are responsible for the following seasons summer and winter, Q.3 rewrites the following statements after correcting them, 1. The earth velocity varies according to the period of revolution, Ans: right, 2. if we observe from the northern hemisphere , we see the apparent movement of the sun, Wrong: if we observe from the both northern and southern hemisphere and we see the apparent movement of the sun, 3. The dates of equinox change every year, Ans: right, 4. North Canada experience summer from September to March 8, Ans: wrong –north Canada experience winter from September to March, 5. When it is summer in South Africa, Australia has winter, Wrong: when it is summer In south, Australia has summer, 6. Duration of daytime is less on the vernal and autumnal equinoxes, ans: wrong – duration of daytime is equal on the vernal and autumnal equinoxes