# RGPV Previous Year Question Papers Engineering Physics Sept 2009

**Time:3 Hrs Max Marks:100 Min Marks:35**

**Note:**Attempt any five questions taking one question from each unit.All question Carry equal marks.

**UNIT-I**

Q.1.(a) State and explain the Heisenburg’s uncertainty principle with its verification? 10

(b) Derive both time dependent and independent Schrodinger wave equation for a non- relativistic particle in potential V(vector r).also give physical significance of wave function? 10

**OR**

Q.2.(a) Explain De-broglie theory of matter waves.Discuss the experimental verification of de-Broglie eqaution of wavelength? 10

(b)Write down Schrodinger equation for a particle in box.Solve it to obtain eigen functions and show that the eigen values are discrete? 10

**UNIT-II**

Q.3.(a) Explain the formation of interference fringes by means of Fresnel’s Biprism when a monochromatic sources of light is used and derive an expression for the fringe width? 10

(b) What do you mean by law of malus? Explain how light is polarised by reflection. A ray of light is incident on a surface of benzene of refractive index 1.50 .If the reflected light is linearly polarised, calculate the angle of refraction? 10

**OR**

Q.4.(a) Give the teory of plane transmission grating ? Why the white light gets dispersed after diffraction through grating?10

(b) What is polarisation of light? State Brewster’s law? 5

(c) In newton’s rings experiment,the diameter of the 15th ring was found to be 0.59 cm and that of the 5th ring was 0.336 cm, If the radius of the plano-convex lens is 100 cm, calculate the wavelength of light used? 5

**UNIT-III**

Q.5.(a) Why do we say that a nucleus behaves like a drop of liquid? what are the essential features which are common in drop of liquid and a nucleus? 5

(b) Explain the working of Geiger-Muller Counter with the help of a diagram? 5

(c) Discuss the construction and working of BainBridge mass spectrography? 10

**OR**

Q.6.(a) Describe giving neccesary theory and diagram the working of a betatron. The magenetic flux within the stable orbit in a betatron changes at a constant rate of 15 wb/s .What would be the energy of an electron which undergoes 10^6 revolution? 10

(b) Explain the principle and working of nuclear reactor? 10

**UNIT-IV**

Q.7.(a) Show that the energy distribution of electrons in solid consists of allowed and forbidden bands.Distinguish between insulators, semiconductors and conductors on the basis of band theory of solid? 10

(b) What is Hall effect?Give an elementary theory of hall effect. Mention some important uses of Hall effect? 10

**OR**

Q.8.(a) Describe with suitable diagrams the construction and action of PN junction diode. Discuss the physical processes that take place in and near the depletion layer? 10

(b) What do you understand by nanomaterials ? Describe the two approaches of nanomaterial fabrication with example of processes. state some important applications of nano materials? 2,4,4

**UNIT-V**

Q.9.(a) Distinguish between the ‘Spontaneous Emission’ and ‘Stimulated Emission’ of radiation. Obtain the relation between the transition probabilities of the two? 10

(b) Explain construction and working of any one LASER with suitable diagrams? 10

**OR**

Q.10 (a).Explain how light propagates through an Optical fiber from one end to other? 4

(b) What is meant by acceptance angle ? Derive the expression for acceptance angle and how its value does not depand on the physical dimensions of the fiber? 10

(c) Define numerical aperture (N.A.) of an optical fiber. A step index fiber in air has NA of 0.16,a core refractive index of 1.45 and core diameter of 60 micro meter.Determine the normalized frequency for the fiber when light at a wavelength of 0.9 micrometer is transmitted? 2,4