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JiQues1) What are non luminous objects?, Ans) objects that do not give light of their own are known as non luminous objects. For eg- chair ,table, etc., Ques2) Differentiate between artificial and natural sources of light by giving example?, Ans) Natural source of light are those which are naturally luminous . Example- sun, stars etc, whereas, artificial sources of light are man made luminous objects .for example-diyas, candle etc., Ques3) How is shadow formed?, Ans) A shadow is formed when the path of light is blocked by an opaque object., Ques4) What are the various conditions for the formation of shadow?, Ans) three conditions are there1) Source of light, 2) Opaque object, 3) Screen on which shadow is formed, Ques5) What happens to shadow when the source of light is moved closer and away from the object?, Ans) When the source of light is moved closer to the object the size of shadow increases., When the source of light is moved away from the object the size of shadow decreases., Ques6) What are eclipses ?, Ans) Eclipses are shadows cast by the earth and the moon by blocking the sunlight falling on each other., Eclipses occur due to the revolution of the earth and moon., Ques7) Explain the formation of day and night on the earth ., Ans) Formation of day and night are caused due to rotation of earth. When half of the earth is facing sun, the other half is on the opposite side of the sun,then half side which is facing the sun experiences day, time while the other half is experiencing night., Due to rotation each half changes its position in every 12 hours ,so one rotation (24 hours) is considered, as one day., Ques8) Define penumbra and umbra region ., Ans) Umbra:- A fully dark inner region of the shadow cast by an opaque object is known as umbra., Penumbra:- A partially dark outer region of a shadow, Cast by an object is known as Penumbra., Ques9) How a lunar eclipse occur?, Ans)A lunar eclipse occurs when the earth comes in between the moon and the sun which cast a shadow, of earth onto the moon .Lunar eclipse only happens during a full moon light.

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Ques10) Describe the formation of solar eclipse., Ans)When the sun ,moon and the earth are in a straight line ,the moon very briefly blocks the light of, the sun. This phenomenon is Known as solar eclipse. A solar eclipse occurs on new moon day.