# OPTICS (5 marks & 3 marks)

1. Derive mirror formula
2. Derive an expression for refraction at a spherical surface and hence derive lens makers formula
3. Derive thin lens formula
4. Derive an expression for the effective focal length of two thin lenses in contact.
5. Discuss refraction of monochromatic light through a prism and Derive prism formula.
6. Define dispersion and its cause. Explain the formation of rainbow.
7. State and explain Huygens' wave theory of light and explain the laws of reflection and refraction using it
8. Explain the principle of superposition and deduce the conditions for constructive and destructive interference when two waves superpose each other.
9. What are coherent sources? Describe any one method to obtain coherent sources with neat labeled diagram.
10. Describe Young's double slit experiment and draw a graph showing the distribution of light intensity on the screen.
11. Derive an expression for the bandwidth in Young's double slit experiment and hence show that bright fringe and dark fringe are of equal width.
12. Draw a diagram showing the experimental arrangement for Fraunhoffer diffraction at a single slit.
13. Deduce the conditions for maxima and minima in diffraction at a single slit.
14. Show that the width of central maximum is double the width of secondary maxima in diffraction at a single slit.
15. State an prove Brewster's law of polarisation
16. Draw a ray diagram showing the formation of image by a simple microscope and derive expression for its magnifying power.
17. Draw a ray diagram showing the formation of image by a compound microscope and derive expression for its magnifying power.
18. Draw a ray diagram showing the formation of image by an astronomical telescope in normal adjustment and derive expression for its magnifying power.
19. Which are the defects of human eye? How are they corrected?
20. What is Fresnel distance? derive an expression for it.
21. Explain how diffraction effects limit the resolving power of microscopes and telescopes.