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#### Optics Three Marks Questions

12th Standard EM

Reg.No. :
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Physics

Time : 01:00:00 Hrs
Total Marks : 45
15 x 3 = 45
1. Obtain the equation for resultant intensity due to interference of light.

2. Explain the Young's double slit experimental setup and obtain the equation for path difference.

3. Obtain the equations for constructive and destructive interference for transmitted and reflected waves in thin films.

4. Obtain the equation for of microscope.

6. Explain the experimental determination of material of the prism using spectrometer.

7. Light travelling through transparent oil enters in to glass of refractive index 1.5. If the refractive index of glass with respect to the oil is 1.25, what is the refractive index of the oil?

8. A coin is at the bottom of a trough containing three immiscible liquids of refractive indices 1.3, 1.4 and 1.5 poured one above the other of heights 30 cm, 16 cm, and 20 cm respectively. What is the apparent depth at which the coin appears to be when seen from air medium outside? In which medium the coin will be seen?

9. A optical fibre is made up of a core material with refractive index 1.68 and a cladding material of refractive index 1.44. What is the acceptance angle of the fibre kept in air medium? What is the answer if there is no cladding?

10. The thickness of a glass slab is 0.25 m. it has a refractive index of 1.5. A ray of light is incident on the surface of the slab at an angle of 60o. Find the lateral displacement of the light when it emerges from the other side of the mirror.

11. A biconvex lens has radii of curvature 20 cm and 15 cm each. The refractive index of the material of the lens is 1.5. What is its focal length? Will the focal length change if the lens is flipped by the side?

12. What is the focal length of the combination if a lens of focal length –70 cm is brought in contact with a lens of focal length 150 cm? What is the power of the combination?

13. A monochromatic light is incident on an equilateral prism at an angle 30o and emerges at an angle of 75o. What is the angle of deviation produced by the prism?

14. Obtain the equation for bandwidth in Young's double slit experiment,

15. Mention different parts of spectrometer and explain the preliminary adjustments.