Mumbai University Previous year question papers
I Year Examination Dec 2009
N.B.1. Question No.1 is compulsory.
2. Attempt any four questionsfrom Q. Nos. 2 to 7. ..
3. Use suitable data whereverrequired.
4. Figures to the right indicate full marks.
5. Illustrateyour answerwith sketches wherevernecessary.
I. Attempt any five :-
(a) Describe phase measurement by using CRG.
(b) Draw following planes in Cubic Unit Cell
(1 I 1) (I 01) (1 0 I)
(c) Describe working of liquid Crystal display.
(d) State applications of Hall effect.
(e) State applications of Super Conductivity.
(f) Explain Industrial applications of x-rays.
2. (a) A loudspeaker emits energy in all directions at the rate of 1.5 J/sec. What is the intensity level in dB at a distance of 20 m ?(Standard intensity level of sound= 10- 12 w/m2).
(b) What are Crystal imperfections? How they arc formed? What is their Significance? 10
3. (a) State Sabines formula. Explain the terms involved in it. How Sabines formula can be made applicable to acoustics of auditorium ?
(b) Show that the ratio of Hall electric field EHto the electric field E which is responsible for the Current in n-type Semiconductor water kept in a Uniform magnetic field B is given by-EH=~E nep
4. (a) Sodium is a BCC Crystal. It’s density is 9,6 x 102kg/m3and atomic weight is 23. Calculate the lattice Constant for Sodium Crystal.
(b) What is Super Conductivity? Describe Type-I and Type -II Super conductors and prove that Super Conductors are perfect diamagnetic.
5. (a) Whatis fermienergyandfermi-diracdistributionfimction? Showthat in intrinsicSemiconductors fermi level lies midway between Conduction band and valance band.
(b) Estimate the number of Frankel defects per mm3 in Silver chloride if energy of formation of Frankel defects is 1’5 ev at 700ok. The molecular weight of AgCI is 0’143 kg/mol and Specific density is 5’56.
6. (a) How ultrasonic waves are produced? Illustrate any two applications of Ultrasonics.
(b) Explain the concept of Electrostatic focussing in electron optics.
7. Write short notes on any three :-
(a) Miller indices
(c) X-rays in Crystallography
(d) Conduction in Semiconductor diode.