NCERT, Class 10th SCIENCE
Chapter- The human eye and the colourful world
Q1. Why do stars twinkle?
Q2. Explain why the planets do not twinkle ?
Q3. Why does the sun appear reddish early in the morning?
Answers
Answer:
1. due to change in intensity of light
when star light enters our atmosphere due to temperature, atmospheric conditions it is affected and this cause light of star to twinkle when seen from ground.
2.they do not twinkle because they are closer to our earth.
3.because in early mng sun is at horizon and sun rays have to travel a long distance to reach our eyes .and because all other colours than scatter before reaching us other than red.red colour scatters the most at that. time.
that's why it appear reddish
Answer:
1. the twinkling of stars is due to atmospheric refraction of Stars light. as a consequences the number of Ray's entering the pupil of the eye goes on the changing with the time and the stars appear twinkling
2. unlike stars, planet do not twinkle. stars are so distant that they appear as pinpoints of light in the night sky ,even when viewed through a telescope. because all the light is coming from a single point, its path is highly susceptible to atmospheric interference
3.during the sunrise, the light Ray's coming from the sun have to travel a greater distance in the earth's atmosphere before reaching our eyes. in this journey, the shorter wavelength are able to reach our eyes. since blue colour has a shorter wavelength and red cloud has a longer wavelength and the red colour is able to reach our eyes after the atmospheric scattering of light. therefore, the sun appears reddish early in the morning