1.Explain clearly Huygen's Principle for the wave propagation of light.

2.what do you mean by perfectly coherent sources?

3.What is meant by spatial and temporal coherence of light source?

4.Explain the results of Young's expt. On interference of light with diagram.

5.Write about the conditions to produce good and observable interference fringes.

6.How are the coherent sources are realised in practice?

7.what is Fresnel biprism? Describe how the wavelength of monochromatic source of light can be determined with its help.