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APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
FIRST SEMESTER B.TECH DEGREE EXAMINATION(2019 SCHEME), DECEMBER 2019
Course Code: PHT110
Course Name: ENGINEERING PHYSICS B
(2019-Scheme)

Max. Marks: 100 Duration: 3 Hours
PART A
Answer all questions, each carries 3 marks.
1 Derive the differential equation of a damped harmonic oscillator (3)
2 Find the equation of a progressive wave of amplitude 2cm, frequency | Hz (3)

and velocity 20 cm/s moving along positive x-axis.

9 How will you test the planeness of a surface using air wedge? (3)
4 Distinguish between Fresnel and Fraunhofer classes of diffraction. (3)
5 What is de Broglie hypothesis of matter waves? Write the equation of (3)

de Broglie wave length
6 Give three medical applications of nanotechnology. (3)
7 What is meant by intensity of sound? Give the equation connecting (3)

intensity and amplitude.

8 What are ultrasonic waves? Mention any fourproperties of them. (3)
9 What is an optical resonator? Explain its role in laser emission. (3)
10 Discuss the advantages of optical fibre over conventional transmission lines. (3)
PART B
Answer one full question from each module, each question carries 14 marks
Module-I

1] a) What is amplitude resonance? Give any two examples. Derive an expression (10)
for resonant frequency. What is sharpness of resonance?

b) In the case of a forced harmonic oscillator, the amplitude of vibrations (4)
increases from 0.05 mm at very low frequencies to a value 7.5mm at the
frequency 210117, Find Q- factor, damping constant and relaxation time.

12 a) Obtain an expression for fundamental frequency of transverse vibrations in a (10)
stretched string.

0) A wave of wavelength 30cm is travelling through a 300m long wire whose (4)
mass 15 15kg. If the wire is under tension of IkN, compute the speed and

frequency of the wave.

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