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

NAS-101

(Following Paper ID and Roll No. to be filled in your Answer Book)

Paper ID : 181504

--- Content provided by⁠ FirstRanker.com ---

Roll No.

B.Tech.

(SEM. I) THEORY EXAM. 2015-16

ENGINEERING PHYSICS-I

[Time: 3 hours]

--- Content provided by‍ FirstRanker.com ---

[Total Marks : 100]

SECTION-A

1. Attempt all parts. all parts carry equal marks. Write answer of each part in short. (2x10=20)
   1. How the negative results of Michelson-Morley experiment interpreted?
   2. Find relativistic relation between energy and momentum.
   3. If uncertainty in the position of a particle is equal to de Broglie wavelength, what will be uncertainty in the measurement of velocity?

   --- Content provided by FirstRanker.com ---

   4. Write the characteristics of wave function.
   5. Why the center of Newton's ring is dark?
   6. Define plane of polarization and plane of vibration.
   7. If the kinetic energy of a body is twice its rest mass energy, find its velocity.
   8. Explain de-Broglie's hypothesis. Discuss the outcome of Davisson-Germer's experiment in detail.

   --- Content provided by⁠ FirstRanker.com ---

   9. Explain the phenomenon of interference in thin film due to reflected rays.
   10. A diffraction grating used at normal incidence gives a yellow line of a certain spectral order superimposed on a blue line (=4800Å) of next higher order. If the angle of diffraction is sin^-1 (3/4), calculate the grating element.

SECTION-B

Note: Attempt any three questions from this section. (3×10=30)

--- Content provided by FirstRanker.com ---

1. What do you mean by proper length? Derive the expression for relativistic length. Calculate the percentage contraction of a rod moving with a velocity of 0.6c in a direction inclined at 30° to its own length.
2. Show that the relativistic invariance of the law of conservation of momentum leads to the concept of variation of mass with velocity.
3. State Heisenberg's uncertainty principle. Prove that electron cannot exist inside the nucleus and proton can exists.
4. Explain the construction and working of Nicol prism.
5. Prove that v_p x v_g = c². Where v_p=phase velocity and v_g=group velocity.

--- Content provided by⁠ FirstRanker.com ---

6. Calculate the numerical aperture, acceptance angle and the critical angle for a typical optical fibre. A step index fibre has core refractive index 1.468, cladding refractive index 1.462. Compute the maximum radius allowed for a fibre, if it supported only one mode at a wavelength 1300 nm.

SECTION-C

Note: Attempt any two questions from this section.(2×15=30)

1. (a) Derive the Galilean transformation equations and show that its acceleration components is invariant.
   (b) Explain the physical significance of wave function. Derive Schrodinger's time independent wave equation.

--- Content provided by​ FirstRanker.com ---

2. Explain the formation of Newton's rings. If in a Newton's rings experiment, the air in the interspace is replaced by a liquid of refractive index 1.33 in what proportion would the diameter of the rings changed?
3. Discuss the different types of optical fibre in detail.
4. In a Ruby laser, total number of Cr⁺³ is 2.8x10¹⁹. If the laser emits radiation of wavelength 7000Å calculate the energy of the laser pulse.

Physical Constants :

Mass of electron m = 9.1x10^-31 kg

--- Content provided by FirstRanker.com ---

Mass of proton m_p = 1.67x10^-27 kg

Speed of light c=3x10⁸ m/s

Planck's Constant h=6.63x10^-34 J/s

Charge on electron e = 1.67x10^-27 kg

Boltzmann's Constant k=1.38x10^-23 m² kg s^-2k^-1

--- Content provided by FirstRanker.com ---

Source: FirstRanker.com