Applied Physics 1 - May 2012

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.

Attempt any FIVE.

1(a) What is the difference between sound intensity and loudness?(3 marks) 1(b) Draw the following with respect to cubical unit cell
{1 2 3}, {2 0 0}, {2 3 0}(3 marks) 1(c) Define superconductors, critical temperature, critical magnetic field.(3 marks) 1(d) Explain different phasors of liquid crystal.(3 marks) 1(e) Explain use of CRO to determine phase difference between two signals.(3 marks) 1(f) Explain cavitation effect and its applications.(3 marks) 1(g) Explain the characteristic X-ray spectra.(3 marks) 2(a) Define Piezoelectric effect. Explain construction and working of piezoelectric Oscillator.(8 marks) 2(b) Explain the concept of Fermi level. What is the probability of an electron being Thermally excited to conduction band in silicon at 20^oC. The band gap energy is 1.12eV. Given Boltzman constant 1.38 x 10²³ J/K(7 marks) 3(a) Find the following parameters for HCP structure (i) co-ordination No. (ii) Atomic Radius (iii) No of atoms per unit cell (iv) APF (v) c/a ratio.(8 marks) 3(b) State Bathe law. Explain electrostatic focusing.(7 marks) 4(a) Derive Bragg's equation. Explain construction and working of Bragg's Spectrometer.(8 marks) 4(b) An electrically deflected CRT has an anode voltage 2000 V and parallel deflecting plates 1.5 cm long and 20 mm apart. If the screen is 50 cm from the center of deflecting plates, find (i) Beam speed (ii) the deflection sensitivity of the tube and (iii) Deflection Factor of the tube.(7 marks) 5(a) Define Reverberation time. Explain how the reverberation time is affected by (i) size (ii) Nature of it's wall surface (iii) Audience(8 marks) 5(b) What is eco sounding techniques? Velocity of ultrasonic in mild steel is 5.9 x 10³ m/s. Velocity of ultrasonic in brass measured by an ultrasonic gauge meter, calibrated for mild steel is 4.3 x 10³ m/s, if thickness of brass plate measured by the gauge meter is 15 cm. What is the real thickness?(7 marks) 6(a) What is Meissner effect? Explain Type I and Type II superconductors.(8 marks) 6(b) The radiation of an x-ray tube operated at 50 kV are diffracted by a cubical KCl FCC Crystal of molecular weight 74.6 and density 1.99gm/cc. Calculate (i) The shortest wave length (ii) Glancing angle for first order reflection.(7 marks) 7(a) What is Hall effect? State it's significance. How can mobility be determined by using Hall Effect?(8 marks) 7(b) Calculate P.F. for Chromium having BCC structure. Given density 5.98 gm/cc, atomic weight 50.(7 marks)