# SSC Worksheet for chapter-4 Wonder Of Light-II class 10

## Find SSC Worksheet for chapter-4 Wonder Of Light-II class 10

CLASS-10

BOARD: SSC

Physics Worksheet-4

TOPIC: Wonder Of Light-II

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1. In dispersion of sunlight by a glass prism_______ light is deviated the least and _______light is deviated the most.

2. Danger signals are red in colour become red colour scatters__________

3. Sky appear dark to a person in space as there is no _________ to scatter sunlight

4. Define Refraction

5. State Laws of Refraction

6. Explain with example the phenomenon of scattering of light.

7. Explain how the duration of the day is increased by four minutes due to refraction.

8. Explain why stars twinkle and planets do not twinkle

9. Explain how it is possible to enjoy a rainbow at fountains in any season.

10. Speed of light in water and glass is 2.25×108m/s and 2×108m/s respectively. Calculate refractive index of

(i) glass w.r.t water

(ii) water w.r.t glass

11. Refractive index of glass is 1.5. Speed of light in air is 3×108m/s. Find speed of light in glass.

12. What is the angle of refraction, when a light ray is incident normal to the interface between any two medua?

13. The speed of light in water and glass is 2.25×108 m/s and 2×108m/s respectively. What is the refractive index of :

(a) water with respect to glass?

(b) Glass with respect air?

14. Draw a neat and labeled diagram to show dispersion of a beam of sunlight passing through a glass prism.

### Solutions: to worksheet-4 Topic-Wonder Of Light-II

1. Red, violet

2. The least

3. Atmosphere

4. The phenomenon of change in the direction of light when it passes from one transparent medium to another is called refraction.

5. Laws of refraction

1. The incident ray and the refracted ray are on the opposite sides of the normal at the point of incident and all three lie in the same plane.

2. For a given pair of media, the ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant.

Ifiis the angle of incidence and r is the angle of refraction then, Sin i/Sin r = constant

This constant is called as the refractive indexof second medium with respect to the first medium. It is denoted byη.

6. When light passes through a substance or gas, a part of it is absorbed and the rest scattered away. The basic process in scattering is absorption of light by the molecules followed by re-radiation in different directions.The strength of scattering depends on the size of the particle causing the scattering and the wavelength of light

7. Due to atmospheric refraction, the sun remains visible even after it sets and is visible even before it rises. Thus, the refraction increases the length of the day. Calculations show that sun rises 2 minutes earlier and sets 2 minutes later due to refraction. This means, the day becomes 4 minutes longer due to refraction.

8. It has to do with the difference in the visual sizes of stars versus planets. Although stars are much, much larger than the planets in our solar system, the planets appear larger because they are much closer to us. Stars are so far away that their light is literally a point in the sky. All of the light from any given star comes through the atmosphere and to our eyes in exactly the same direction and is bent in exactly the same way by turbulence in the air. A star will "disappear" briefly when its light is bent away from our eyes, then reappear when its light is not bent off course to our eyes. Planets, because they are closer, do not appear as points in the sky. Their light, traveling to our eyes along many different paths, is not all simultaneously bent away by atmospheric turbulence, and so they do not twinkle.

9. (i) One can observe and enjoy the rainbow by standing in front of a water fountain in the evening facing the east.

(ii) One can also enjoy it in the morning under the same condition just by facing the west. Therefore it is possible to enjoy a rainbow at fountains in any season.