ENGINEERING PHYSICS (UTU QUESTION PAPER - 2022)

 ENGINEERING PHYSICS (UTU QUESTION PAPER - 2022)

ENGINEERING PHYSICS (UTU QUESTION PAPER - 2022)

Note: - Attempt all questions:All Questions carry equal marks

Q 1. Attempt any four parts of the following (5 x 4 = 20)

(a) What are matter waves? Briefly describe Davlssion-Germer experiment which proved existence for matter wave.

(b) Sate Heisenberg uncertainty principle. Apply It to prove the non-existence of the electron

in the atomic nucleus.

(c) A hydrogen atomis 0.53 A0 In radius.Use uncertainty principle to estimate the minimum energy in eV, an electron can have in this atom

(d) Derive time independent and time dependent Schrodinger wave equation.

(e) An electronls confined to move between two rigid walls separated by 1A0• Find the

de-Broglie's wavelength represent ng the first three allowed energy states of the electron and the corresponding energies.

Q 2. Attempt any four parts of the following (5 x 4 = 20)

(a) What are coherent sources? Give var ous methods to derive two coherent sources from a single source of fight.

(b) Derive the expression for diameter of bright and dark Newton's rings in reflected light.

(c) Two glass plats enclosing a wedge-shaped air film touching at one edge are separated by a wire of 0.03 mm diameter at distance of 15 cm from the edge. Monochromatic light

 

(A=6000 A0

 

from a broad source falls normally on the film.Calculate the fringe width.

 

(d) Show that the relative intensities of the successive maximum are nearly

 

1:,,.,.i ::s,.::

 

'*

49112

 

-- -i.n s.ingIe s11t d 1.ff ractron.

 

 

(e) What is Rayleigh criterion of limit of resolution? Find the resolving power of diffraction grating.

Q 3. Attempt any t\Yo parts of the following (10 x 2 = 20)

{a) Whatis Fermilevel? How docs it change with temperature? Calculate the temperature at which there Is 1% probability that a state,.with an energy 2 eV Is occupied. Given Fermi energy fa=l.5 eV.

(b) Ex-plain Hall Effect and hence derive the expression for Hall voltage and carrier concentration.

A n-type Ge sample has a donor density of 1021/ m3• It is arranged in a hall experiment

 

having a magnetic field of 0.2 Wb/m2 and the current density is 600 A/m2

 

Determine

 

the hall voltage if d= 4 mm.

(c) What do you mean by Meissner effect? Explain typeIand type IIsuperconductor. For a superconductor, the criticalfields are 0.176 T and 0.528 T for 14 K and 13 K respectively.Calculate the transition temperature and critical fields at 0 K.

Q4. Attempt any two parts of the following: {10 x 2 = 20)

(a) Explain spontaneous and stimulated emission of radiation.What are Einstein's A and B coefficients? Establish relation between them.

(b) Explain the term population inversion.Give the construction and working of He-Ne laser. How itis better than ruby laser.

(c) Explain the acceptance angle for an opticalfiber. Deduce an expression for the same. Calculate the numerical aperture,acceptance angle and criticalangle of an opticalfiber with nl (core) =1.55 and n2 (dadding) =1.50.

Q5. Attempt any two parts of the following: (10 x 2 = 20)

(a) Derive electromagnetic wave equation in free space. Also show that electromagnetic waves are transverse in nature.

(b) Deduce Poynting theorem for the now of energy In an electromagnetic field and define Poynting vector. Find the electric and magnetic field at 2 m distance from a 500 Watts electric bulb.

{c) Using Gauss's law, calculate electric field due to a solid charged sphere having charge Q and radius R (i) at a point outside the charged sphere at distance r (ii) at a point lying on the surface of charged sphere {Iii) at a pointinside the charged sphere.