Guru Gobind Singh Indraprastha Vishwavidyalaya 2003 B.Tech ETPH – 103 Subject : Applied Physics-I - Question Paper

End-Term exam
First Semester [B.Tech] – December 2003

Paper Code : ETPH – 103 Subject : Applied Physics-I

Time : three Hours
Maximum Marks : 75

Note : Attempt any five ques. in all.


Q1
( a )
What is meant by the principle of superposition of waves? discuss in brief how it provide rise to the phenomenon of beats and stationary wave.
6

( b )
Is any loss of energy involved in either of these cases?
3

( c )
Plane harmonic waves of frequency 500sec-1 are produced in air with displacement amplitude 1.00 x 10-3 cm. Deduce (i) the pressure amplitude (ii) the energy density.
6



Q2
( a )
What is a satellite? Derive the formula for the orbital velocity and time period of a satellite.
8

( b )
Show that the velocity of escape of the body from the earth's surface is v2 times the velocity for a circular orbit just above the earth's surface.
7



Q3
( a )
For a driven oscillator of natural frequency ?/2p defined by m x`` + r x` - k x = F sin ( p t ). Deduce an expression for velocity amplitude xo. Show that for cases p>> ?, p= ? and p<< ?, this amplitude is governed by the inertia factor, the resistance factor and the spring factor respectively.
8

( b )
An under-damped harmonic oscillator has its amplitude decreased to 1/10th of its initial value after 100 oscillations. If its time period be 1.15 sec., compute (i) the damping constant (ii) the relaxation time.
7



Q4
( a )
define Michelson's- Interferometer and explain the conditions for obtaining (i) circular fringes (ii) straight fringes with this interferometer.
5+5

( b )
compute the thickness of a double refracting plate capable of producing a path difference of ?/4 ranging from extraordinary and ordinary waves.
5



Q5
( a )
discuss how a zone plate acts like a converging lens having multiple foci.
5

( b )
describe the terms (i) induced absorption (ii) spontaneous emission (iii) induced emission.
5

( c )
How induced emission explains Lasers?
5



Q6
( a )
describe the term expectation value of an observable volume. obtain the expectation values of (i) potential-energy (ii) linear momentum (iii) total energy.
8

( b )
discuss the construction and working of a Geiger-Muller counter. explain the significance of plateau curve in G.M. counter.
7



Q7
( a )
State and deduce mathematical expression for the legal regulations of addition of relativistic velocities. Show that in no case the resulting velocity of a material particle be greater than c.
6+3

( b )
A proton has a velocity equal to 0.999c in the laboratory. obtain energy and momentum as observed in the identical direction with velocity and momentum as observed in the identical direction with velocity 0.999c w.r.t the laboratory. Mp=1.6725 x 10-24 gm.
6



Q8


Write short notes on ANY THREE
three x 5

(a)
Ruby laser



(b)
Central forces



(c)
Electron-Microscope



(d)
Reveberations

Earning:   Approval pending.