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Reg No.: Name:
APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
First Semester B.Tech Degree Regular and Supplementary Examination December 2020 (2019 Scheme)

Course Code: PHT100
Course Name: ENGINEERING PHYSICS A

(2019 Scheme)
Max. Marks: 100 Duration: 3 Hours
PARTA
Answer all questions, each carries 3 marks. Marks

1 What is amplitude resonance? Give two examples. (3)
2 What is the relation between path difference and phase difference in wave (3)

motion?

Newton’s rings are circular but air wedge fringes are straight. Why? (3)
4 Give 3 differences between Fresnel and Fraunhofer classes of diffraction. (3)
5 What is meant by quantum mechanical tunnelling? Name two electronic (3)

devices based on this phenomenon.
6 Explain the concept of quantum confinement. (3)
7 Define magnetic flux density and magnetic field intensity. Give the relation (3)

between them.

8 Compare displacement current and conduction current. (3)
9 Give a qualitative account of BCS theory. (3)
10 Explain the working of a Photo diode. (3)
PART छ
Answer one full question from each module, each question carries 14 marks
Module-I

11 a) Frame the differential equation of a damped harmonic oscillator and deduce (10)
its solution. Compare the time-displacement curve in three cases.
b) The frequency of a tuning fork is 200112, If its quality factor is 8 x10*, find (4)
the time after which its energy becomes 1/10" of its initial value.
12 a) Derive the differential equation for transverse wave in a stretched string and (10)
hence obtain the expression for fundamental frequency.
b) Calculate the fundamental frequency of a string of 1 m long & mass 2g when (4)

stretched by a weight of 4 kg.

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