Answer question numbers 1–4 on the basis of your
understanding of the following paragraph and the related
studied concepts.
The sight of sunrise and sunset is the prettiest. Isn’t it? But if you
notice carefully, you’ll notice the sun appears red during sunrise
and sunset. Do you know, why? Well, it’s because of ‘Scattering of
Light’. But what does one mean when they say scattering of light?
The molecules of air and other fine particles in the atmosphere
have size smaller than the wavelength of visible light. These are
more effective in scattering light of shorter wavelengths at the blue end than light of longer wavelengths at the red end. The red light has a wavelength about 1.8 times greater than blue light. Thus, when sunlight passes through the atmosphere, the fine
particles in air scatter the blue colour (shorter wavelengths) more
strongly than red. The scattered blue light enters our eyes. If the
earth had no atmosphere, there would not have been any
scattering. Then, the sky would have looked dark.
Why do stars appear higher than they actually are? Does this have
something to do with the scattering of light? Well, the answer to this
is ‘No’. Stars appear higher than they are because of ‘Atmospheric
Refraction’.
1. Explain giving reason why the sky appears blue to an observer
from the surface of the earth?
2. Why do stars twinkle?
3. ‘Danger’ signal lights are red in colour. Give reason.
4. What will be the colour of sky for an astronaut staying in the
international space station orbiting the earth? Justify your
answer giving reason.
Answers
Answer:
1. Sky appears blue as its wavelength is comparable to the particles of clouds present in atmosphere ... hence blue gets scattered
2. Stars Twinkle due to atmosphere refraction, resulting in twinkling as light from the Stars passes various layers of atmosphere
3. RED has the Highest wavelength in the visible light spectrum
4. No Color i.e. Black as no atmosphere is present to refract rays from Sun
Explanation:
Read About Rayleigh Scattering
Answer:
1 .Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.
2 stars do not twinkle the dust particles and other objects in the air obstruct our vision and stars seem to twinkle
3. danger signal is red because wavelength of red colour is more than other colours and can be seen from a long distance also
4,the colour for an astronaut of sky is black because in space there are no particlez to scatter light