**1. State Huygen’s principle in the wave theory of light. Using the principle prove laws of refection.**

**2. Prove laws of refraction using Huygen’s principle .**

**3. Describe Michelson method to determine velocity of light.**

**4. Describe young’s double slit experiment and then derive the expression W= XD/d using the path difference between the light sources S**

_{1}and S_{2}.**5. The distance between the first and 6**

^{th}bright fringe formed in young’s double slit experiment is found to be 12.5mm. The separation between the slits 0.12 mm and the distance of the screen from the slits is 60 cm.**Calculate the ( i) Fringe width (ii) Wave length of light used ( in nm)**

**(Fringe width =2.5 mm,**

**8**

**= 500nm )**

**6. In a biprism set up for the determination of wave length of light, the slit is illuminated by a monochromatic of light wave length 590nm. The distance between slit and biprism is 5 cm and distance of the screen from the biprism is 95.0cm. The fringe width is found is be 590micro metre. Calculate the distance between the virtual images of the slit formed by the biprism. (d= 1mm)**

**7. State Brewster’s law for polarization of light.**