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B.E./B.Tech.Degree Examinations, November/December 2010Regulations 2008First SemesterCommon to all branchesPH2111 Engineering Physics ITime: Three Hours Maximum: 100 Marks

Answer ALL Questions

Part A - (10 x 2 = 20 Marks)

1. List down the disadvantages of piezoelectric e®ect.

2. Compare transmission and re°ection modes of non destructive testing using ultra-

sonics.

3. Why is population inversion necessary to achieve lasing?

4. How is electrons and holes con¯nement made in the active region of heterojunction

laser?

5. What are the di®erent types of classi¯cation of optical ¯bres?

6. Explain dispersion in an optical ¯ber.

7. De¯ne blackbody and blackbody radiation.

8. What i s meant by wave function?

9. An element has a HCP structure. If the radius of the atom is 1.605ºA, ¯nd the height

of unit cell.

10. What i s meant by a `Schottky pair'?

Part B - (5 x 16 = 80 Marks)

11. (a) With a neat diagram explain the method of production of ultrasound using

piezoelectric crystal. (16)

OR

11. (b) (i) With a neat diagram, discuss the principle and inspection method of ul-

trasonic °aw detector. (12)

(ii) Calculate the velocity of ultrasonic waves in water using acoustic grat-

ing. The frequency of the ultrasonic wave generated by transducer is 2

MHz. The di®raction angle measured i s 8'45" in the third order di®rac-

tion pattern. Wavelength of laser light used in this experiment is 6328ºA.

(4)

12. (a) Discuss the Einstein's theory of stimulated absorption, spontaneous and stim-

ulated emission of radiation. What are the conditions for light ampli¯cation?

(16)

OR

12. (b) (i) What is hologram? What are the necessary steps involved in recording

and reconstruction of a hologram? (12)

(ii) Compare holography with photography. (4)

13. (a) (i) Explain the basic structure of an optical ¯bre and discuss the principle of

transmission of light through optical ¯bres. (5)

(ii) Derive an expression for numerical aperture. (5)

(iii) Brie°y discuss a technique of optical ¯bre drawing. (6)

OR

13. (b) Explain the concept of optical ¯ber sensors and describe in detail about any

two sensors. (6 + 10)

14. (a) (i) What is meant by matter wave? (2)

(ii) Derive an expression for the wavelength of matter wave. (8)

(iii) Describe an experiment that veri¯es the existance of matter waves. (6)

OR

14. (b) Solve Schrodinger's wave equation for a particle in a box (one dimensional)

and obtain the energy and eigen function. (16)

15. (a) (i) De¯ne atomic packing factor. (2)

(ii) Calculate the number of atoms, atomic radius, coordination number and

atomic packing fraction for BCC and FCC structures. (10)

(iii) The distance between successive planes of Miller indices (111) i s 2.078ºA

for a metal having FCC structure. Find the atomic radius and volume of

its unit cell. (4)

OR

15. (b) (i) De¯ne the terms polymorphism and allotropy. (2)

(ii) Explain in detail the crystal defects and their types. (14)

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