# Engineering Physics Important Questions for Mid Exam

**UNIT-III**

1.Explain piezo and Ferro electricity?

2. Define the following a) Electric dipole b) Dipole movement c) Dielectric constant d) Polarisability e)

Susceptibility f) Displacement vector

3. Derive the following equations a) Internal fields in solids (or) Lorentz method (or) Local fields in solids (or)

clasius-mosotti equation. b) Expression for four polarization process.

4. Explain the following a) Permeability b) Field intensity c) Magnetic induction (B) d) Magnetization e)

Susceptibility

5. Explain piezo and Ferro electricity?

6. Explain origin of magnetic movement with Bohr magneton?

7. Explain the classification of Dia, para, Ferro, Ferri, antiferro on the basis of magnetic movement?

8. Explain the following a) Domain of ferro magnetism b) Hysterisis curve c) Hard and soft materials d)

Superconductivity e) Meissner effect f) Type-I and Type-II superconductors g) Applications of superconductors.

**UNIT-4**

1. Derive the following: (a) Interference in thin films. (b) Newton’s rings experiment.

2. Give an expression for Fraunhoffer Diffraction due to single slit and ‘n’ slits.

3. Diffraction grating experiment.

4. Explain the construction and working of Nicol’s prism.

5. Explain the following: (a) characteristics of LASERS. (b) Distinguish b/w Spontaneous and stimulated

emission. (c) Population Inversion. (d) Lasing action. (e) Applications of LASERS.

6. Give an expression for Einstein coefficients and their relations.

7. Explain the construction and working of the following: (a) Ruby LASER. (b) He-Ne LASER. (c) Hetero and

Homo semiconductor LASERS.

8. What is FIBRE? Explain principle in optical fibre and their applications.

9. Explain construction of a fibre. Give an expression for Acceptance angle, cone and Numerical aperture.

10. Explain the types of fibres and optical fibres in Communication systems.

**UNIT-5**

1. Distinguish between intrinsic and extrinsic semiconductors.

2. Derive an expression for the density of holes in the valence band of an intrinsic Semiconductor

3. Derive an expression for density of electrons in intrinsic semiconductors.

4. Derive an expression for carrier concentration of p-type semiconductors.

6. Explain Hall effect and its importance

7. Explain the variation of Fermi level with temperature in the case of p-type semiconductors.

8. Explain the variation of Fermi level with i. Donor concentration ii. Acceptor concentration, in the case of

extrinsic semiconductors.

9. What is Hall effect? Derive an expression for Hall coefficient for p-type semi-conductor.

10.Derive an expression for density of holes in intrinsic semiconductors

11.What is Hall effect? Derive an expression for Hall coefficient for n-type semiconductor.

12.Derive an expression for carrier concentration of n-type semiconductors.

13. Explain the variation of Fermi level with temperature in the case of n-type semiconductors.

14.Derive an expression for density of electrons in intrinsic semiconductors.

15. Explain the variation of Fermi level with temperature in the case of p-type semiconductors

16.Derive an expression for carrier concentration of n-type semiconductors. Explain Hall effect and its

importance. Derive an expression for density of holes in intrinsic semiconductors[7+8]