Download AKTU B-Tech 1st Sem 2015-2016 EAS 101 Engineering Physics I Question Paper

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EAS-101

Paper ID : 199121

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B. Tech. (SEM. I) THEORY EXAMINATION, 2015-16

ENGINEERING PHYSICS-I

[Time: 3 hours]

[Total Marks : 100]

SECTION-A

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1. Attempt all parts. All parts carry equal marks. Write answer of each part in short. (2x10=20)
   1. Is earth an inertial frame? Explain.
   2. What is the significance of mass energy relation?
   3. Two independent sources cannot produce interference. Why?
   4. What happens when Young's double slit experiment is immersed in water?
   5. What will be the effect on the intensity of the principal maxima of the diffraction pattern when a single slit is replaced by a double slit?

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SECTION-B

2. Attempt any five questions from this section. (10x5=50)
3. Derive the expression for time dilation. Show that it is a real effect.

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4. Deduce an expression for the variation of mass with velocity. At what speed does the mass of an object become 2.25 times its rest mass?
5. Discuss the formation of interference fringes due to a wedge-shaped thin film seen by normally reflected sodium light. In Newton's ring experiment, the diameter of the 4th and 12th dark rings are 0.400 cm and 0.700 cm respectively. Deduce the diameter of the 20th ring.
6. Obtain the intensity expression for the single-slit Fraunhofer diffraction pattern. Light of wavelength 5500Å falls normally on a slit of width 22.0×10^-5 cm. Calculate the.
7. Describe the process of construction and reconstruction of an image on a hologram. Also, describe the application of holography.

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SECTION-C

9. Attempt any two questions from this section. (15x2=30)
10. (a) Show that space-time or interval between two events remains invariant under Lorentz transformation.
    (b) Show the effect of introducing a thin mica sheet in the path of one of the interfering beams in Young's double-slit experiment.
    (c) Find the mass and speed of an electron with an energy of 2 MeV.

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11. (a) Explain the formation of a spectrum by a plane diffraction grating.

EAS-101

11. (b) Explain how the wavelength of sodium light can be calculated from the Fresnel biprism experiment.
    (c) If the population ratio between two energy states in a Ruby laser is 2×10^-40, emitting a light beam of wavelength 6943Å. Find the temperature of energy states.
12. (a) Discuss the difference between single-mode fiber and multimode fiber.
    

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    (b) Explain the construction and working of a Nicol prism.
    (c) A step index fiber has a core refractive index of 1.466 and a cladding refractive index of 1.460. Compute the maximum radius allowed if the fiber supports only one mode by using a wavelength of 5000Å.

Physical Constants:

Mass of electron, m = 9.1 x 10^-31 kg

Mass of proton, m_p = 1.67 x 10^-27 kg

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Speed of light, c = 3 x 10⁸ m/s

Planck's constant, h = 6.63 x 10^-34 J/s

Charge on electron, e = 1.6 x 10^-19 C

Boltzmann's constant = 1.38 x 10^-23 m²kgs^-2K^-1

EAS-101

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