BE (1st Year)
Applied Physics- I
Values of some useful physical constants
Charge of electron ‘e’ = .1.6xlO-19C
Mass of electron ‘m’ = 9.0×10-31kg
Speed of light’c’ = 3.0xl0sw/sec.
Planck’s constant ‘h’ = 6.62 x 10-34 J sec
(a) Describe Michelson – Morley experiment and show how negative results obtained from the experiment were interpreted ?
(b) Deduce the expression for variation of mass with velocity according to theory of relativity.
(c) (i) A distant galaxy in the constellation Hydra is receding from the earth at 6.12xl07w/s. By how much is.a green spectral line of wave length 500nm emitted by this galaxy shifted towards the red end of the spectrum ?
(ii) How much electric energy could theoretically be obtained by annihilation of 1 gm of matter
(a) (i) Derive Newton’s formula for the focal length of a combustion of two thin lenses
(ii) Write the properties of ultrasonic waves.
(b) What is the Magnetostriction effect ? Draw circuit diagram of magneto striation oscillator and explain its working . What are I the advantage of magnetostriction method ?
(c) For an empty assembly hall of size 20x 15×10 m3 the reverberation time in 3.5 sec. Calculate the average absorption coefficient of the hall . What area of the wall should’; be covered by the curtain so as reduce the reverberation time to 2.5 sec. Given the absorption coefficient of curtain cloth is 0.5.
Q3 (a) Describe and explain the formation of Newton’s rings in’ reflected light prove that in reflected light
(i)Diameters of the dark rings are proportional to the aquaria roots natural numbers and
(ii)Diameter of bright rings are proportional to the square roots of the odd natural numbers
(b) Discuss the Fraunhofer diffraction at a single slit. Extend this theory to the case of a plane transmission grating .
(c) (i) What should be minimum number of lines in a grating which will just resolve in the second order the lines whose wavelengths are 5890 A and 5896.4 ?
(ii) The refractive index of glass is 1.5. Calculate the polarizing angle for it. Also calculate the angle of refraction
4. (a) What is a truth table ? Write and explain the Boolean expressions for the OR,AND and NOT gates.
(b) What is Boolean Algebra ? Describe commutative , associative and distort abusive laws of Boolean Algebra.
(c) State and prove De-Morgan’s theorem for two variables.
5. (a) What is compton effect ? Derive an expression for the Compton shift why it is not observed in the visible region of electrognetic radiation ?
(b) Explain de-Broglie’s. concept of matter waves . Give an account of Davisson and Gerber experiment to. show the wavelike character.of p beam of electrons.
(i) Find the shorts wavelength present in the radiation from ah X ray machine whose accelerating potential is 50,000V.
(ii) Calculate the longest wavelength that can be analysed by rock salt crystal of spacing d = 2.82 A, (x) in the first order (y) in the second order.