Class 10 MAHARASHTRA STATE TEXTBOOK BUREAU Solutions Science Chapter 6 - Refraction of Light
Refraction of Light Exercise Ex. 6
Solution 1
a. Refractive index depends on the wavelength of light.
b. The change in direction of propagation of light rays while going from one medium to another is called refraction.
Solution 2.a
Solution 2.b
a) A rainbow is a combined effect of several natural processes.
b) It is the combined effect of dispersion, refraction and total internal reflection of light.
c) When sunlight is incident on a water droplet, there is refraction and
dispersion of light when it passes from air to water, internal reflection of
light inside water droplet and again refraction when it passes from water to air.
d) Dispersion of sunlight takes place as the tiny water droplet acts as a prism.
e) Thus, a rainbow is seen when the Sun is behind the observer and water droplets are in the front.
Solution 3.A
iv. Changing refractive index of the atmospheric gases
The twinkling of a star is due to atmospheric refraction of starlight. The starlight, on entering the earth's atmosphere, undergoes refraction continuously before it reaches the earth. The atmospheric refraction occurs in a medium of gradually changing refractive index. Since the atmosphere bends starlight towards the normal, the apparent position of the star is slightly different from its actual position.
Solution 3.B
ii. Refraction of light
The rising sun is visible to us before actual sun rise and after actual sunset because of the atmospheric refraction of light. The density of air is higher near the surface of earth. The rays from the sun coming through space enter from rarer to the denser medium and hence bend slightly towards normal at each refraction and become visible to us before actual sunrise. Therefore, sun appears to rise few minutes earlier than the actual sunrise and for the same reason it continues to be seen a few minutes after it has actually set.
Solution 3.C
d. 2/3
Solution 4.a
Solution 4.b
