Applied Physics 1 - Dec 2011
First Year Engineering (Semester 1)
TOTAL MARKS: 60
TOTAL TIME: 2 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Use suitable data wherever required.
(4) Figures to the right indicate full marks.
Answer any five :-
1 (a) Draw the following planes (121), (100), (111)(3 marks) 1 (b) State any three applications of superconductivity(3 marks) 1 (c) How Lissajous figure are used to determine phase difference?(3 marks) 1 (d) What are ultrasonic waves? State magnetostriction effect.(3 marks) 1 (e) State Sabine's formula.(3 marks) 1 (f) Calculate atomic packing factor for FCC crystal structure ?(3 marks) 1 (g) Show the position of Fermi level in intrinsic semiconductor, p-type semiconductor and n-type semiconductor.(3 marks) 2 (a) Explain Dimond crystal structure with proper diagram. Calculate the number of atoms per unit cell, atomic radius and atomic packing factor for diamond unit cell.(8 marks) 2 (b) What is cavitation effect? Kind the natural frequency of vibration of quartz plate of thickness 2mm,. Given: Young's modulus for quartz 8 x 1010 N/m2 and density 2650 kg/m3. Calculate the change in thickness required if the same plate is to be used to produce ultrasonic waves of 3 MHz.(7 marks) 3 (a) Explain reverberation and reverberation time. Explain various methods for design of good acoustics.(8 marks) 3 (b) What is lattice parameters? Aluminium has density 2.7 gm/cm3. It has atomic weight 27 and lattice parameter is 4.05 A?. Determine the type of crystal structure followed by Aluminium and calculate the atomic radius. Given Avogadro's number NA = 6.023 x 1023/gm mole.(7 marks) 4 (a) what is superconductivity and critical temperature? Descibe type I and type II superconductor.(8 marks) 4 (b) Define mobility of charge. Find resistivity of germanium at 300 ?K. Given density of carriers is 2.5 x 1019/m2. Mobility of electron is 0.39 m2/V-Sec and mobility of hole is 0.19 m2/V-Sec. Charge of electron is 1.6 x 1019C.(7 marks) 5 (a) State Hall effect and what is the signification of hall effect? N-type Ge sample has donor concentration 1021 atoms/m3. What hall voltage would you expect if current 1 x 10-3 A and if 0.5 magnetic field is applied across 2 mm thick sample.(8 marks) 5 (b) What is piezoelectric effect? Explain with neat labeled diagram the construction and working of Piezoelectric oscillator.(7 marks) 6 (a) State and explain terms in Bragg's law of X-ray diffraction. Calculate the glancing angle on cube (100) of rock salt having lattice constant 2.84 A? corresponding to first order diffraction maximum for X-ray of wavelength 1.541 A? (8 marks) 6 (b) Explain construction and working of CRO.(7 marks)
Solve/Explain any three;
7 (a) A class room has dimension 20 x 15 x 10 m3, the reverberation time is 3 sec. calculate total absorption of its surfaces and average absorption coefficient.(5 marks) 7 (b) Liquid crystal and different phase of liquid crystal (5 marks) 7 (c) Point defects in crystal (5 marks) 7 (d) Meissner effect(5 marks)