Engineering Physics - Oct 2012

First Year Engineering (Semester 2)

TOTAL MARKS: 50
TOTAL TIME: 2 HOURS (1) Solve Q.1 or Q.2, Q.3 or Q.4, Q.5 or Q.6, Q.7 or Q.8
(2) Assume suitable data, if necessary.

Answer any one question from Q1 & Q2

1 (a) Prove that in Newton's Ring by reflected light the diameter of bright ring are proportional to the square root of the odd natural number.(6 marks) 1 (b) Explain any one application of Ultrasonic Waves.(3 marks) 1 (c) he average reverberation time of a hall is 1.5 sec. and the area of the interior surface is 3340m². If the volume of the hall is 13000m³. Find the absorption coefficient.(3 marks) 2 (a) Explain how piezoelectric effect can be used for generating Ultrasonic Waves?(6 marks) 2 (b) Define fringe width for wedge shaped film, obtain an expression for it.(3 marks) 2 (c) Find the half angular width of the central maxima in the fraunhofer diffraction pattern of slit having width 10 ×10^-5 cm. When illumininated by light having wave length 5000 A°(3 marks)

Answer any one question from Q3 & Q4

3 (a) tate the Phenomena of Double Refraction. Hence explain Huygen's Wave Theory of Double Refraction.(6 marks) 3 (b) Draw energy band picture for P-N junction in case of (i) Zero Bias (ii) Forward Bias (iii) Reverse Bias.(3 marks) 3 (c) A silver wire is in the form of a ribbon 0.5cm wide and 0.1 mm thick. When a current of 2A passes through the ribbon perpendicular to 0.8 Tesla Magnetic Field. Calculate the Hall Voltage produced.
(Given : Density of Silver = 10.5 gm/cc, Atomic Weight of Silver = 108, Avogadros No. 6.02 × 10²³ gm/mole)(3 marks) 4 (a) Derive an expression for Conductivity in Semiconductor.(6 marks) 4 (b) Explain any one application of Laser.(3 marks) 4 (c) How should the Polarizer and Analyzer be oriented to reduce intensity of beam to (i) 50% (ii) 0.25 of its original intensity ?(3 marks)

Answer any one question from Q5 & Q6

5 (a) Define Phase Velocity and Group Velocity. Hence obtain the relation between V_p and V_g for DeBroglie Wave.(6 marks) 5 (b) Explain the physical significance of ? and |?|².(4 marks) 5 (c) An electron is bounded by an infinite potential well of width 2 ×10^-8. Calculate the lowest two permissible energies of an electron.
(Give: h=6.64×10^-34 J- sec., m=9.1 × 10^-31 kg)(3 marks) 6 (a) Derive Schrodinger's Time Independent Wave Equation.(6 marks) 6 (b) tate DeBroglie's Hypothesis. Hence obtain the relation for DeBroglie's Wave Length in terms of Energy.(4 marks) 6 (c) he position and momentum of 1 kev electron are simultaneously measured. If its position is located within 1A°. Find the percentage of uncertainty in its momentum.
(Given: h=6.64×10^-34 J-sec., m=9.1×10^-31 kg)(3 marks)

Answer any one question from Q7 & Q8

7 (a) Explain the Phenomena of Super-conductivity. Explain Type - I and Type - II Super-conductors.(6 marks) 7 (b) Explain any two applications of Nano-technology.(4 marks) 7 (c) Explain any two properties of Nano-particle.(3 marks) 8 (a) Explain Synthesis of Metal Nano-particle by Collidal Route Method.(6 marks) 8 (b) Explain BCS Theory of Super-conductivity.(4 marks) 8 (c) State and explain:
(i) Meissner Effect
(ii) Persistent Current(3 marks)