# CSVTU Exam Papers – BE I Year – Applied Physics – I – Nov-Dec 2009

BE (I Year )

Examination-Nov-Dec 2009

Applied Physics – I

Useful Physical Constants

Charge on the electron ‘e’ = 1.6 x 10″19 C

Mass of the electron ‘me‘ 9.1 x 10″31 kg

Mass of the Proton’m p,1.67x TO”27 kg

Mass of the Neutron ‘mp‘ = 1.674 x 10″27 kg

Velocity of light ‘C’ 3 x 108 m/sec – Planck’s constant ‘h* 6.625 x 10″34 J/s

Avogadro’s Number NA 6.02 * 1023 gm-mol

1 Atomic Mass Unit (a.m.u) = 1.66 x10″27 kg Boltzmann’s constant.’Ktf = 1.38 x 10″23 J/K

Permittivity of free space ‘Eo’ = 8,85 x 10″12 F/m

1 A° = 1 0″10m

Q1 (a) At what speed should a clock be moved so that it may appear to lose 1 minute in each hour:

(i)  4.16 x 10-8

(ii) 54 x 1(T6 m/s

(iii)5.4 x 107 m/s

(iv) 2.32 x 107 m/s

(b)  Discuss some of the achievements of the special theory of relativity and in the light of these also discuss that material objects can never have the velocity greater than that the velocity of light.

(c) The concept of length, mass and time which were absolute, before Einstein become relative after Einstein explain it. Deduce an Einstein mass energy relation E = mc2, considering the, variation of mass with velocity,

(d)  (i) Show that x2 + y2 +z2 — c^t2 is invariant under Lorentz transformation.

(ii) A particle in a stationary frames-lies in the x — y plane and has a velocity 0.8 c inclined at 60° to the axis of x. What will be the velocity of the particle as observed by a person in a frame S’ moving relative to S* with a velocity 0.4 c meters/sec.

Q2 Eight Number of cardinal points in a lens system is

(i)  Two

(ii) Four

(iii) Six

(iv) Eight

(b) What are the different methods for the production of ultrasonic waves ? Describe one of them in detail. How will you determine the wavelength of these waves ?

(c) Show that for a coaxial lens system

X1X2 = f-if2

where the symbols’ -have their usual meanings. What do you mean by angle of deviation ?

(d) (i) For an empty assembly hall of size 20 x 15 x 10 m3 theReverberation time is 3.5 sec.Calculate the average absorption coefficient of the hall., What area of the wall should be covered by the curtain so as to reduce the reverberation time to 2.5 sec. Give the absorption coefficient of curtain cloth is 0.5.

(ii)A thin converging lens and a thin diverging lens ‘are placed coaxially at a distance of ‘5 cm. If the focal length of each lens is 10 cm, find for the combination

(a) The focal length

(b) The  power and

(c)  position of the principal points

Q3 (a) A thin film of air between a plane glass plate, and a convex lens- is irradiated with parallel beam of monochromatic light and isobserved under a microscope, you will see :

(i) uniform brightness

(ii) complete.-darkness

(iii) field crossed over by concentric bright and dark rings.

(iv) field crossed over by parallel bright and darks rings.

(b) Explain how interference fringes may be obtained with the help Qf a Fresnel’s Biprism. How may the arrangement be used to determine the wavelength of a given monochromatic source of light ?

(c)  What is meant by resolving power of a diffraction grafikg ? Show that the resolving power is given by the product of the total no. of ruling and the order of spectrum.

(i) In Newton’s rings experiment the, diameter of the 15’h ring was found to be 0.590 cm and that of the 5th ring was 0.336 cm. If the radius of the piano-convex lens is 100 cm. Calculate the wavelength of the light used

(ii) Calculate the thickness of a mica sheet required for making a quarter wave plate for k = 5460 A0. The thickness of refraction for the ordinary and extra ordinary rays in mica are 1.586 and I.592.

Q4  The 2’s complements of (1011)2 will be

(i) (01100)2

(ii) (0101)2

(iii) (1100)2

(iv) (0100)2

(b) How are three basic logic gates OR, AND and  NOT realised by using

(i)a universal NOR gate

(ii) a NAND gate

(c)  State and verify the De-Morgan’s theorems’ with’ the I truth tables.

(d) Do the following operations

(i) Simply the expressions (AB+C) (AB + D)   11/2

(ii) Add (7F)16 and (BA)16    11/2

(iii)If x = (10101.01)2 Y = (110.10)2. Find X x Y    11/2

(iv) Divide (1101001)2 by (101 )2   1/12

(v) Subtract (10001 )2 from (10011)2  01

Q5   (a)Describe De-Broglie concept of matter waves. D De-Broglie wavelength. Describe Davission Germer’s experiment to study the diffraction of electrons

(b) What is Heisenberg uncertainty principle ? Exp airs how St is the Outcome of the wave description c f a particle ? Arrive Heisenberg uncertainty principle with the help of a Simple thought experiment.

(c) What is the minimum voltage applied to an X-ray tube to produce X-ray of 1 A° ?

(ii) Electrons accelerated by a potential of 250°V enter the electric field at an angle of incidence of 50° and get refracted through an angle of 30°. Find the potential difference between the two regions.