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JNTU B.Tech I ENGINEERING PHYSICS - I Previous Question Paper (December - 2017 - R16)

B.Tech | I | I | R16 | December - 2017

Answer PaperPaper Code: 131AHMaximum Marks: 75Time: 3 hours

This question paper contains two parts A and B. Part A is compulsory. Part B consists of 5 Units. Answer any one full question from each unit.

Part A

125 marks
a

What are the conditions for constructive and destructive interference?

2 marks

Answer

For constructive interference, the path difference between two waves must be an integral multiple of the wavelength,

Δ = nλ
, where
n = 0, 1, 2, ...
. For destructive interference, the path difference must be an odd integral multiple of half the wavelength,
Δ = (2n + 1)λ / 2
.

b

What are the two types of diffractions? Give differences between them.

3 marks

Answer

The two types of diffraction are Fresnel diffraction and Fraunhofer diffraction. In Fresnel diffraction, the source and screen are at finite distances from the obstacle, and the wavefront is spherical or cylindrical. In Fraunhofer diffraction, the source and screen are effectively at an infinite distance, requiring lenses to produce a plane wavefront.

c

Explain Malus’s law.

2 marks

Answer

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d

Explain spontaneous and stimulated emission of radiation with energy level diagram.

3 marks

Answer

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e

Explain the basic principle of an optical fiber.

2 marks

Answer

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f

Explain the term ‘numerical aperture’ and ‘acceptance angle’.

3 marks

Answer

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g

Write an expression for inter planar spacing of a cubic crystal structure.

2 marks

Answer

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h

Derive the packing fraction of FCC crystal.

3 marks

Answer

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i

State Bragg’s law and give the condition for constructive interference.

2 marks

Answer

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j

Write notes on ‘point defects’ in crystals

3 marks

Answer

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Part B

210 marks
a

With a ray diagram discuss the interference in thin films(Reflected light).

3 marks

Answer

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b

Derive the condition for constructive and destructive interference in the case of reflected system.

4 marks

Answer

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c

A parallel beam of light λ=5890 A0 is incident on a glass plate (µ=1.5) such that angle of refraction is 60 degree. Calculate the smallest thickness of the plate which will make it appear dark by reflection.

3 marks

Answer

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OR
310 marks
a

Discuss the theory of Newton rings with relevant diagram in the reflected light.

3 marks

Answer

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b

Derive the expressions for the diameters of dark and bright rings.

4 marks

Answer

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c

Newton rings are observed in the reflected light of wavelength 5900 A0. The diameter of tenth dark ring is 0.5cm. Find the radius of curvature of the lens used.

3 marks

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410 marks
a

What is double refraction?

3 marks

Answer

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b

Explain briefly optic axis and its characteristics.

3 marks

Answer

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c

Discuss the construction and working of Nicol Prism.

4 marks

Answer

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OR
510 marks
a

What are Einstein’s coefficients? Derive relation between them.

4 marks

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b

What do you understand by Population Inversion?

2 marks

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c

Describe He-Ne Laser and its applications.

4 marks

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610 marks
a

Explain briefly different types of optical fibers.

3 marks

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b

Derive numerical aperture in terms of fractional difference in refractive indices.

4 marks

Answer

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c

Write any three applications of optical fibers.

3 marks

Answer

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OR
710 marks
a

Draw the block diagram of an optical fiber communication system and explain the function of each block.

4 marks

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b

Derive an expression for acceptance angle for an optical fiber.

3 marks

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c

What are the different losses in optical fibers? Write brief note on each.

3 marks

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810 marks
a

Classify the various Bravais lattice types in the crystal systems.

3 marks

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b

Zinc has HCP structure. The height of the unit cell is 0.494 mm. The nearest neighbor distance is 0.27 mm. Calculate the volume of the unit cell.

4 marks

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c

Describe the structure of diamond.

3 marks

Answer

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OR
910 marks
a

Determine the inter-planar spacing between the two parallel planes with miller indices (h,k,l) in a cube of side ‘a’.

3 marks

Answer

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b

Sketch the following planes of a cubic unit cell: (001), (120) and (211).

4 marks

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c

A plane makes intercepts 1, 2 and 3 A0 on the crystallographic axes of an ortho-rhombic crystal with a:b:c = 3:2:1. Determine the miller indices of this plane.

3 marks

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1010 marks
a

How the X-ray diffraction can be employed to determine the crystal structure? Explain.

3 marks

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b

Describe with neat diagram, Laue’s method of determination of crystal structure.

4 marks

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c

X-rays of wavelength 1.5418 A0 are diffracted by (111) planes in a crystal at an angle 30 degree in the first order. Calculate the inter atomic spacing.

3 marks

Answer

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OR
1110 marks
a

Write notes on surface defects in crystals.

3 marks

Answer

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b

What is Burger’s Vector? Explain.

3 marks

Answer

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c

Explain edge dislocation and screw dislocation.

4 marks

Answer

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About this paper

This page contains the question paper of ENGINEERING PHYSICS - I from JNTU for B.Tech EEE I I, December - 2017, R16.

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