 MORE IN Engineering Physics
SPPU First Year Engineering (Semester 1)
Engineering Physics
May 2016
Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

Solve any one question from Q.1(a,b,c) Q.2(a,b,c)
1(a) A thin film of uniform thickness is illuminated by monochromatic light. Derive an expression for path difference for the reflected rays system. Hence obtain the conditions for constructive and destructive interference.
6 M
1(b) What is reverbration time? Explain any two measures to control reverberation time in an auditorium.
3 M
1(c) Calculate the reverberation time for an empty hall of volume 1200m3 that has total sound absorption of 450m2 sabine. When the hall is completely occupied, total sound absorption is further increased by 450m2 sabine. Hence calculate the reverberation time.
3 M

2(a) What is piezoelectric effects? Draw neat and labelled diagram for piezoelectric oscillator and hence explain its construction and working.
6 M
2(b) What is diffractionof light? Differentiate between Fresnel and Fraunhoffer diffraction( two points).
3 M
2(c) A monchromatic light of wavelength 5500 A° incident normally on a slit of width 2×10-4 cm. Calculate the angular position of first and second minimum.
3 M

Solve any one question from Q.3(a,b,c) Q.4(a,b,c)
3(a) Why is the combination of Helium and Neon gases chosen in He-Ne laser system? Explain construction and working of He-Ne laser system with the help of energy level diagram.
6 M
3(b) Define Fermi level for a semiconductor . Draw a neat and labelled diagram showing position of Fermi level in intrinsic semiconductor and in N-type semiconductor.
3 M
3(c) A sample of inrinsic germanimum at room temperature has a carrier concentration 4.41×1022cm3, Donor impurity is added in the ratio 1 donor atom per 10epsilon; atoms /cm3 of germanium. Determine the resistivity of the material thus formed.
(Given: μe 3800 cm2/V.s)
3 M

4(a) What is Hall effect? Derive the expression for Hall voltage and Hall coefficient. State applications of Hall effect.
6 M
4(b) What is double refraction? Draw neat and labelled diagram ( either for positive or negative crystal) showing propagation of light within a doubly refracting crystal when optic axis is: i) parallel to crystal surface
ii) perpendicular to crystal surface.
3 M
4(c) Sugar solution is kept in a 20 cm long tube. When plane polarized light is passed through this solution, its plane of polarization is rotated by 10°. If the concentration of sugar solution is 0.07575, calculate the specific rotation of sugar.
3 M

Solve any one question from Q.5(a,b,c) Q.6(a,b,c)
5(a) Deduce Schrodinger's time independent wave equation.
6 M
5(b) What is de-Broglie hypothesis. Derive an expression for de-Brogile wavelength for an electron when it is accelerated by potential difference 'V'.
4 M
5(c) Calculate the energy (in eV) with which a proton has to acquire de-Brogile wavelength of 0.1A°.
3 M

6(a) State and explain Heisenberg's uncertainty principle. IIIustrate the principle by electron diffration at a single slit.
6 M
6(b) Explain physical significance of wave function ψ and (ψ)2. State the mathematical conditions that wave function ψ should satisfy.
4 M
6(c) A neutron is trapped in an infinite potential well of width 1A°. Calculate the vallues of enegy and momentum in its ground state.
3 M

Solve any one question from Q.7(a,b,c) Q.8(a,b,c)
7(a) Explain critical magnetic field or superconductor. Differentiate between type-I and type-II superconductors (four points).
6 M
7(b) With necessary diagram, explain physical method for synthesis of nanoparticles.
4 M
7(c) State applications of nano-particles. Explain any one application.
3 M

8(a) What is nanotechnology? Explain optical and electrical properties of nano-particles.
6 M
8(b) Explain Meissner effect and show that supercondutors exhibit perfect diamagnetism.
4 M
8(c) State applications of superconductors. Explain any one application.
3 M

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