No. ofPrinted Pages: 4 IBAS-OOll
B.Tech. AEROSPACE ENGINEERING
(BTAE)
Term-End Examination
December, 2015

BAS-001 APPLIED PHYSICS
Time hours Maximum Marks: 70
Note: Question no. 1 is compulsory. Attempt any five questions from questions no. 2 to 9. Use of scientific calculator is permitted. Assume missing data, If any.

1. The equation for a transverse wave in a stretched string is
y 4 sin 21t((t/0.05) with length x expressed in cm and t in sec. Find the
amplitude frequency, and (iii)velocity of the wave.

The energy of a simple pendulum is 1 Joule, when its length is 2 metres and amplitude of motion is 3 cm. Calculate its energy when

its length is not changed but amplitude is changed to 5 cm,

its amplitude is not changed but length is changed to 1 metre.

The potential energy of a harmonic oscillator in its resting position is 10 Joules and the average kinetic energy is 5 Joules. Calculate the total energy at any instant of its motion.

Define forced harmonic oscillation and resonance.

Find the equation of a plane progressive wave travelling along x-axis in positive direction with amplitude 0.02 frequency 110 Hz and speed 330 m/s.

Define group and phase velocity.

In Young's double slit experiment, the separation of the slit is 1.9 mm and the fringe spacing is 0.31 mm at a distance of 1 m from the slit. Calculate the wavelength of light.

In Fraunhofer diffraction due to a narrow slit, a screen is placed 2 m away from the lens to obtain the pattern. If the slit width is 0.2 mm and the first minima lies 5 mm on either side of the central maxima, find the wavelength of light.

What is the momentum of a photon of wavelength 6 x

Calculate in electron volt, the energy of a quantum of light of wavelength 5.3 x m.

Mention any three shortcomings of Bohr's theory.

Define induced absorption and spontaneous emission.

State the postulates of special theory of relativity.

Calculate the speed of an electron so that it has double its rest mass.

Give any three applications of lasers.

2. A particle is moving with simple harmonic motion in a straight line when the distance of the particle from equilibrium has the values x1
and x2. The corresponding values of velocity are v1 and v2. Show that

The period of SHM is 2n(x2^2 x1^2/v1^2

The maximum velocity is

Vmax sqrt(v1^2x2^2

3. Define damped harmonic oscillation. Derive the differential equation for a damped harmonic oscillator and discuss the various types of damping.

4. Two coherent sources, whose intensity ratio is 9 16, produce interference fringes. Deduce the ratio of maximum intensity and minimum intensity in fringe system.

5. Define coherent source and explain Young's double slit experiment of interference.

6. Define diffraction and explain Fraunhofer diffraction at a single slit with a neat diagram.

7. Describe the principle, construction and working of a Ruby laser.

8. A single electron revolves around a stationary nucleus of charge Ze, where Z is a constant and e is the magnitude of the electronic charge. It requires 47.2 eV to excite the electron from the second Bohr orbit to the third Bohr orbit. Calculate the kinetic energy, potential energy and the angular momentum of electron in the first Bohr orbit.

9. Describe the Michelson-Morley experiment and explain the physical significance of negative results.