JNTU Exam Papers,I B.Tech Supplimentary Exams,Engineering Physics,Aug/Sep-2008

I B.Tech Supplimentary Examinations, Aug/Sep 2008

ENGINEERING PHYSICS

SET-III

1. (a) What are coherent sources? Why any two independent sources of light cannot produce interference fringes?

(b) With relevant diagram, explain Young’s experiment on the basis of wave theory.

2. (a) Write the expression for resolving power of a telescope.

(b) Explain how resolving power can be improved?

(c) Calculate the linear separation between two points at a distance of 10 km from a telescope objective of width 0.5 m if the wavelength of light used is 600 nm.

3. (a) Explain the following:

i. Polarized light

ii. Double refraction

iii. Non-destructive testing

(b) Calculate the thickness of a quarter wave plate for a monochromatic light of wavelength 600 nm if the refractive indices of ordinary and extra-ordinary rays in the medium are 1.5442 and 1.5533 respectively.

4. (a) Explain the terms

i. absorption

ii. spontaneous emission

iii. stimulated emission

iv. population inversion, relating to laser.

(b) Describe the principle of lasing action.

(c) Mention the important characteristics of laser beam.

5. (a) Define molar specific heat of a solid.

(b) Give an account of the various theories of specific heat of a solid. Discuss any one of them in detail.

6. (a) Explain the term “relative permittivity” of a dielectric medium.

(b) Derive an expression for dielectric loss of a dielectric material.

7. (a) What is meant by hysteresis in magnetic materials?

(b) What are magnetic domains? Explain hysteresis basing on domain theory.

8. (a) What is the effect of stress and temperature on creep?

(b) Explain with neat sketch the different types of creep and their mechanism.

(c) What is the difference between creep and fatigue?

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