(a) Draw a labelled ray diagram to illustrate the dispersion of a narrow beam of white light when it passes through a glass prism.; (b) A star appears slightly higher (above) than its actual position in the sky. Illustrate it with the help of a labelled diagram.(All India - 2012)
Answers
The and for the next part is
The star appear higher than its actual position is because of a phenomenon known as refraction of light.
Refraction
Explanation:
a) When white light passes through a prism, it gets dispersed into the component colors of violet, indigo, blue, green, yellow, orange and red. The reason the component colors separate is because the different colors of light have different wavelengths, and the angle of deviation is different for different wavelength. So we see the rainbow on the other side of the prism.
b) The light rays coming from the star travels through different layers of atmosphere and due to varying optical density, there is bending of light continuously. Due to phenomenon of atmospheric refraction, this bending of light results in curved path of light rays.
Please refer to the attached picture for the diagrams.
