Applied Physics 1 - Dec 2016
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.
Solve any five questionQ.1(a,b,c,d,e,f,g)
1(a) Why the X-rays are preferred to study crystalline solids?(3 marks) 1(b) Draw the following. (1 2 3), [1 2 3], (0 12)(3 marks) 1(c) Write APF values for SC, BCC and FCC.(3 marks) 1(d) Write Fermi-Dirac Distribution function and also mention the meaning of all the terms used over there.(3 marks) 1(e) Explain the concept of Holes in semiconductor.(3 marks) 1(f) Describe Inverse Piezo Electric effect.(3 marks) 1(g) Write three important characteristics of soft magnetic material.(3 marks) 2(a) Show that for instrinsic semiconductor Fermi level is located at the centre of forbidden energy gap. What is the probability of an electron being thermally excited at 27°C for a soild with band gap of 5.6eV. Take K=1.38×10-23 J/K(8 marks) 2(b) Find the following for Diamond cubic crystal sructure i) Atomic radius ii) Number of atoms per unit cell iii) Volume of unit cell. Hence determine its APF.(7 marks) 3(a) State and derive Bragg's law X-ray diffraction. Calculate the galncing angle of rock salt having d=147 A°.Consider first order diffraction and wavelength of x-ray as a 1.541A°.(8 marks) 3(b) A metal ring having cross sectional area 5cm2 turns wound over it. Determine the current required to produce flux of 2 milliweber when i) No airgap ii) Air gap of 1 mm. In both the cases consider relative permeability of metal as 380.(7 marks) 4(a) Draw the diagram representing molecular arrangement of different phases for liquid crystal. State any two aplications of liquid crystal.(5 marks) 4(b) Mention different types of polarizability in dielectric. Explain electronic polarizability.(5 marks) 4(c) The resistivity of intrinstic semiconductor is 2×10-4Ω.cm. If the mobility of electron is 6m2/V-sec, and that of hole is 0.2m2/V-sec, Calculate its intrinsic carrier density.(5 marks) 5(a) Explain with neat diagram construction and function of solar cell.(5 marks) 5(b) The volume of a room is 600m3. The wall area of the room is 220m2. The floor and ceiling area is same and is gien as 120m2. The average floor is 0.06. Calculate the average sound absorption coefficient and reverberation time.(5 marks) 5(c) Derive critical radious ration for ligancy 6.(5 marks) 6(a) Explain Magnetostriction Oscillator to produce Ultrasonic waves.(5 marks) 6(b) Explain the formation of barrier potential in pn junction.(5 marks) 6(c) Explain Ohm's law for magnetic circuit. Also write two points as its comparision with Ohm's law for electrical circuit.(5 marks)