# Dr. A.P.J. Abdul Kalam University BE II SEM (CE/ME) Physics [PH110T] June 2021 Question Paper

Dr. A.P.J. Abdul Kalam University

Bachelor of Engineering

Second Semester Main Examination, June-2021

Physics [PH110T]

Branch: CE/ME

Time: 3:00 Hrs ____ Max Marks 70

Note: 1. Attempt any five questions out of eight.

2. Answer should be precise & to be point only.

3. Assume suitable data if necessary & state them clearly.

Q.1 (a) Define thin film? Explain thin film of interference.

(b) What are coherent? Write the difference between interference and diffraction.

Q.2 (a) Show that formation of interference due to two coherent sources and deduce the

expression for fringe width.

(b) Prove that the diameter of dark rings is proportional to the square root of odd

natural number.

Q.3 (a) What is meant by diffraction of light? Distinguish between Fresnel and

Fraunhoffer classes of diffraction

(b) In Newton’s rings experiment the diameter of the 5th and 10th rings are 4.2 mm

and 7.0 mm respectively. Radius of curvature of Plano-convex lens is 1m. Calculate

the wavelength of light.

Q.4 (a) What are Matter waves? Deduce the expression for wavelength of matter wave.

(b) Define Phase velocity and Group velocity. Derive its relationship between them.

Q.5 (a) What is Compton Effect? Obtain an expression for the shift in the wavelength of

X- ray beam?

(b) Derive Schrodinger’s time dependent wave equations.

Q.6 (a) Monochromatic X-rays of wavelength 0.7078 A° are scattered by carbon. The Xrays scattered at angle 90° with the direction of the incident beam are observed.

What is the wavelength of the scattered X-rays?

(b) What do you meant by nucleus? Also classification of Nuclei.

Q.7 (a) Why do we say that a nucleus behaves like a drop of liquid? What are the

essential features which are common to a drop of liquid and a nucleus?

(b) What are Linear Accelerators? Explain the construction and working of linear

particle accelerator?

Q.8 (a) What is a PN junction diode? Draw the volt-ampere characteristics of PN

junction diode.

(b) Explain three processes occurring when a light wave interacts with matter.

Derive the relationship between the Einstein’s Co-efficient.

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