** BE (I year)
**

**Examination-April- May2010**

**Applied Physics – I**

Q. 1. (a) What is Twin – Paradox ?

(b) Give postulates of special theory of relativity and deduc Lorentz Transformation.

(c)(i) Two particles came towards each other with speed 0.6 c with respect to laboratory. What is their relative speed?

(ii)Deduce Einstein’s mass velocity relation E = mc^{2 }considering the variation of mass with velocity.

(d)(i) With what speed should a clock keeping correct time be moved relative to an observer so that it may seem to lose min. per day.

Q2 What is meant by ultrasonic wave and explain its properties ?

(b) Explain the Magnetostriction Method. Draw circuit diagram for production of ultrasonic wave using magnetostriction method. Explain its working

(c) What is Reverberation Period ? Establish a Sabine formula for reverberation period.

(d)(i) Calculate the reverberation time in a hall measuring

. 45 x100 * 17.78 m3 with the following particulars

(i) 700 m^{2} of plaster,* a _{1t} =* 0.03

(ii) 600 m^{2} of wood, a_{2} = 0.06

(iii)400 m^{2} of glass, a_{3} = 0.25

(iv) 600 seats a_{4} = 0.3

when empty what will happen to the reverberation time with full capacity ? [For one person a_{5} = 4 3]

(ii)Calculate the natural frequency of 40 mm length of a pure iron rod. Given the density of pure iron

is 7.25 x 10^{3} kg/m^{3 }and its Young’s modulus is 11.5 x 10^{9} N/m^{2}. Can you say it is magnetostriction oscillators to produce ultrasonic wave ?

Q3(a) The refractive index Of gtass is 1.5. Calculate, the polarizing angle for it ? Also calculate the angle of refraction.

(b) Describe in detail the experiment to determine wavelength of sodium light using Fresnel’s biprism.

(c)(i) Newton’s rings are formed by using a piano-convex lens of radius of curvature 80 cm, if diameter of 5^{th} dark ring, 1s 0.192 cm and that of 25^{th} is 0.555 cm. Calculate the wavelength of light used.

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

(d)Explain the Rayleigh Criterion of resolution ? Deduce the expression for the resolving power of plane transmission grating.

Q4 (a)What do you understand by a digital circuit ? How does it differ from an analog circuit

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

(c) Give the reason for considering NOR and NAND gates to be universal gates ? Explain your answer with all possible examples

(d) Do as Directed :

(i) Convert (72.612)_{10} to binary system.

(ii) Find 2′s complement of (1010)_{2}

(iii) Divide (11011 )_{2}^{by} (10’0)_{2} ^{1}

(iv)Multiply (1101 )_{2} ^{by} (1100)_{2}

(v)Subtract (01011 )_{2} from (10110)_{2}

(vi)Convert (9FA)_{16} into Decimal system.

(vii) Convert (100101 )_{2} to Octal system

Q5(a) What is meant by wavepacket ? Explain its characteristic.

(b) What is Compton’s Effect ? How could it be explained by Quantum theory .

(c) (i) An electron is inside a box of length 10-^{9}m. Calculate the minimum uncertainty in its velocity. 3

(ii) X rays of wavelength 1.2 A° are scattered by a carbon target at an angle of 60°. Calculate the wavelength of scattered X rays.

(c) What is Heisenberg’s Uncertainty Principle ? On its basis show that electron cannot reside inside the nucleus