# Diffraction of light Exercise

1. Discuss the phenomenon of Fraunhofer diffraction at a single slit and obtain condition for first  minimum from central maximum.

2. What is the difference between Fresnel diffractioin and Fraunhofer diffraction? Derive an

expression for the angular width of central diffraction maximum in the case of Fraunhofer diffraction at a single slit. [Amity Univ., Noida, Dec. 2005]

3. Give the construction of a plane diffraction and for N number of slits in the grating, obtain the condition for first secondary minimum after the central maxima. Also write in general number of  secondary minimum and number of secondary maxima in between two primary maxima.

4. (a) What will be the effect on a diffraction pattern of a grating if the grating element is of the  order of A or less?

(b) How would you increase resolving power of a diffraction grating?

(c) What is Rayleigh criterion of resolution?

(d) Is there any difference in the diffraction pattern due to double slit and interference due to two  sources?

5. What is Rayleigh criterion of resolution? Deduce an expression for resolving power of the

diffraction grating.

6. Discuss the phenomenon of Fraunhofer’s diffraction at a single slit and show that the intensities of the successive maximum are nearly in the ratio of 4/9π : 4/25 π2: 4/49 π2 :…

7. What is meant by diffraction of light? Distinguish between Fresnel and Fraunhofer classes of diffraction.

8. Explain Rayleigh criterion of resolution obtain an expression of resolving power of grating.

9. What do you understand by the resolving power of a grating? Derive necessary expression.

10. Give the construction and theory of plane transmission grating and explain the formation of

spectra by it. Explain what are absent spectra.