** BE (I Year )
**

** Examination-April-May 2009 **

** Applied Physics-I**

**Values of some useful physical constants . **

**Speed of light ‘c’ = 3×1 0^{8}m/sec**

**Planks constant’h’ = 6.62×10″ ^{34}Jsec **

*Charge of* electron ‘e’ = 1l.6×10~^{19}C

**Mass of electron ‘m _{e}‘ = 9.0 x 10~^{31}kg**

**Boltzmann’s constant ‘K’ =1.38×1 0′^{23}joule/k **

**Mass of neutron ‘rh _{n}‘ = 1 .67 x 1’0″^{27}kg**

Q1 (a) What is frame of references?

(b) State fundamental postulates of Einstein’s special theory of relativity. Deduce the Lorentz transformation.

(c) (i) What will be the percentage of length contraction of a rod that is moving with velocity 0.5 C in a direction at angle of 450 with its own length

(ii)Two particles came towards each other with speed 0.8C with respect to laboratory. What is their relative speed ?

(iii) Deduce the variation of mass with velocity prove that

* E ^{2} – P^{2}C^{2} + mo^{2}c*

^{4}Where P is relativistion momentum

Q2 (a) Number of cardinal points in a lens system is :

(i) Two (ii) Four

(iii) Six (iv) Eighth

(b) What are cardinal points of a coaxial optical system ? State their properties and show their positions in a diagram

(c) Explain piezoelectric effect. Draw circuit diagram. Explain its working .

(d) (i)A classroom has dimensions 20x15x5 m^{3}. The reverberation time, is 3.5 sec. Calculate the total absorption

of its surfaces and the average absorption of its surfaces and the average absorption coefficient

(ii) Explain the terms (a) Reflection (b) Reverberation (iii) Echo of sound energy and then shown graphically only the nature of growth and decay of sound energy in a hall due to reverberation.

Q3(a) ) The reflected light is polarized when it is incident at the angle of 57° find our refractive index of material.

(b)(i) Newton’s rings are observed for wavelength = 5890 A ‘The diameter of the 15^{th} dark rink ‘is 0.75cm. Calculate radius of curvature of lens and thickness of air film.

(ii) Odium light of two lines of wavelength 5890 A and 5896. A falls on a grating surface: If-there are 15000 lines/inch on grating surface, then find the angle of separation in second order spectrum.

(c)Describe the detail the experiment to determine “wave length” of sodium light using Fresnel’s baprism.

(d)What do you understand by-polarization of light? Distinguish between polarized and unpolarized light.

Q4 (a) Explain operation of OR, AND gates.

(b) Do as directed :

(i) Convert (43.3125)_{10} to binary system

(ii)Convert (34.56)_{e} to binary system

(iii) Multiply (2A4)_{16} by(>A8)16

(iv) Find 2’s complement of 1010

(v) Simplify A (A+B)

(vi) Multiply (10111)_{2} by (101)2

(vii) Divide (11000)_{5} by (1000)_{2}

(c) State and prove De Morgan’s theorem and give their truth tables.

(d)Define NAND and NOR & Ex-NOR gates and give their truth tables

Q5 (a) The wavelength X associated with a particle of mass m moving with velocity v is given by :

(b) (i) The energy of a neutron at absolute temperature is in the order of kit. Calculate the wavelength of thermal neutrons at 27°C. 4 .

(ii) An electron is in a box of length 10″^{7}m. Calculate minimum uncertainty in its velocity.

(c) What is Moseley’s law ? Explain briefly.

(d) What is Compton effect ? In a Compton experiment, if a beam of X-ray of wavelength O.198 A is scattered at an angle of 60°. then calculate the wavelength of the scattered ray.