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Dr. Pauls Engineering College

B.E./B.Tech Degree Examinations

PH2161 ENGINEERING PHYSICS – IIMODEL EXAMINATION

TIME: 3 Hrs Max :100 marks

Answer All the Questions

PART – A (10 x 2 =20)

1. Define mean free path of a electron.

2. Define Fermi level, and give its importance.

3. Differentiate between n-type and p-type semiconductor.

4. Write a short note on Fermi level of intrinsic semiconductor.

5. Mention any two important application of ferrites.

6. What are Cooper pairs?

7. Define dielectric breakdown and dielectric strength.

8. What is meant by ferroelectricity? Mention its uses.

9. Explain shape memory effect.

10. What are the applications of carbon nanotubes.

PART – B (5 x 16 = 80)

11) a) Deduce mathematical expression for electrical conductivity and thermal

conductivity of a conducting material and hence obtain weidemann-Franz

law (16)

(OR)

b) (i) Explain qualitatively the effect of temperature on Fermi function (6)

(ii) Derive an expression for the density of energy states (10)

12) a) (i) Obtain an expression for carrier concentration of holes in intrinsic

semiconductor and show that Fermi level at 0 K lies at the middle of 

valence band and conduction band (10)

(ii) Derive the conductivity of the charge carrier in an extrinsic semiconductor 

and derive its band gap (6)

(OR)

b) (i) Explain the phenomenon of Hall effect (4)

(ii) Derive an expression for Hall co-efficient for n-type and p-typesemiconductor and also state how Hall voltage is related (12)

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13) a) (i) Explain hysteresis on the basis of domain theory (6)

(ii) Distinguish between soft and hard magnetic materials (4)

(iii) Describe the structure of ferrites (6)

(OR)

b) Briefly explain the following

(i) Meissner effect (4)

(ii) Type I & Type Ii superconductor (4)

(iii) High Tc superconductor (4)

(iv) cryotron (4)

14) a) Define and explain different polarization mechanism in dielectrics with

necessary polarizability (16)

(OR)

b) Define Internal field. Obtain the expression for internal field using Lorentz

method and hence deduce clausius - mosotti equation (16)

15) a) (i) What are shape memory alloys? Give two examples (4)

(ii) Explain the following characteristics of shape memory alloysshape memory effect, pseudo elasticity, Hysteresis (12)

(OR)

15) b) (i)Discuss briefly the electrical, mechanical and thermal properties of carbon

nano tubes (6)

(ii) Explain the following methods of producing carbon nano tubes

a) Pulsed Laser Deposition (5)

b) Chemical Vapour Deposition (5)

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