Give reasons.
(1) The sky appears dark instead of blue to a person located in space.
(2) Stars twinkle at night.
(3) The sun appears reddish early in the morning.
(4) It is possible to enjoy a rainbow at fountains in any season.
Give reasons.
(1) The sky appears dark instead of blue to a person located in space.
(2) Stars twinkle at night.
(3) The sun appears reddish early in the morning.
(4) It is possible to enjoy a rainbow at fountains in any season.
(1) The sky appears blue when viewed from the Earth because of the scattering of the light. Sky appears dark instead of blue from space because there is no atmosphere in the outer space that can scatter the sunlight.
(2) Stars emit their own light and they twinkle due to the atmospheric refraction of light. Stars are very far away from the Earth. Therefore, they are considered as point sources of light. When the light coming from the stars enters the Earth’s atmosphere, it gets refracted at different levels because there is variation in the air density at the different levels of the atmosphere. When the star light refracted by the atmosphere is near to us, it appears brighter than when it is further away. Therefore, it appears as if the stars are twinkling at night.
(3) During sunrise, the light rays coming from the Sun have to travel a greater distance in the Earth’s atmosphere before they reach our eyes. In this journey, the shorter wavelengths of lights are scattered out and only longer wavelengths are able to reach our eyes. Since blue colour has a shorter wavelength and red colour has a longer wavelength, the red colour is able to reach our eyes after the atmospheric scattering of light. Therefore, the Sun appears reddish early in the morning.
(4) In a fountain when water falls from a very high point, it strikes the rocks below whereby a lot of spherical water droplets are suspended into the air. These water droplets suspended in the air, when subjected to light, act as small spherical prisms which disperse light into its spectrum and send colours out in different angles.
(1) The sky appears blue when viewed from the Earth because of the scattering of the light. Sky appears dark instead of blue from space because there is no atmosphere in the outer space that can scatter the sunlight.
(2) Stars emit their own light and they twinkle due to the atmospheric refraction of light. Stars are very far away from the Earth. Therefore, they are considered as point sources of light. When the light coming from the stars enters the Earth’s atmosphere, it gets refracted at different levels because there is variation in the air density at the different levels of the atmosphere. When the star light refracted by the atmosphere is near to us, it appears brighter than when it is further away. Therefore, it appears as if the stars are twinkling at night.
(3) During sunrise, the light rays coming from the Sun have to travel a greater distance in the Earth’s atmosphere before they reach our eyes. In this journey, the shorter wavelengths of lights are scattered out and only longer wavelengths are able to reach our eyes. Since blue colour has a shorter wavelength and red colour has a longer wavelength, the red colour is able to reach our eyes after the atmospheric scattering of light. Therefore, the Sun appears reddish early in the morning.
(4) In a fountain when water falls from a very high point, it strikes the rocks below whereby a lot of spherical water droplets are suspended into the air. These water droplets suspended in the air, when subjected to light, act as small spherical prisms which disperse light into its spectrum and send colours out in different angles.
