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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI 600 034
B.Sc.DEGREE EXAMINATION -PHYSICS
FIRST SEMESTER APRIL 2018
PH 1501 PH 1502 PH 1503 PROPERTIES OF MATTER ACOUSTICS
Date: 25-04-2018 Dept. No. Max. 100 Marks
Time: 01:00-04:00
PART A
Answer ALL questions: (10x2=20 marks)
1. Calculate Poison's ratio of a material. Given, q=11.25x1010 Nm-2 and
n =4.25x1010 Nm-2
2. Explain the term 'neutral axis' in a bar.
3. What is the effect of temperature on the viscosity of a liquid?
4. The receiver of an air pump has a capacity of 1.5 litres and the pressure of air is 76
cm of Hg. If the barrel has a capacity of 500cc, find the pressure after 3 strokes.
5. Distinguish between cohesive and adhesive forces.
6. An air bubble of radius 0.1mm is situated just below the surface of water. Calculate
the excess pressure inside the bubble. S.T. of water is 0.072 Nm-1 .
7. Mention any two conditions for interference in sound waves.
8. If the frequency of a tuning fork is 400 Hz and the velocity of sound in air is 330ms-1,
find how far the sound would have travelled when the fork completes 3 vibrations.
9. Define reverberation and reverberation time.
10. Define intensity of sound.
PART B
Answer any FOUR questions: (4x7.5=30 marks)
11. Derive an expression for the moment of the couple required to twist one end of a
cylinder through an angle θ while the other end is fixed.
12. Derive an expression for the depression at the loaded end of a cantilever.
13. Compare the coefficient of viscosities of two liquids using Ostwald Viscometer.
What are the advantages of Ostwald viscometer?
14. Using Quinke's method, determine the angle of contact of mercury.
15. Discuss the vibrations of an air column in an open organ pipe.
Compare the fundamental frequencies of an open end and closed end
pipes of the same length.
16. Discuss any five applications of ultrasonic waves.
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PART C
Answer any FOUR questions: (4x12.5=50 marks)
17. Define the various types of elastic constants and obtain the relation connecting
them.
18. Derive Poiseuille's formula for the rate of flow of a liquid through a capillary tube.
Discuss Mayor's modification of Poiseuille's formula for the flow of gas through a
capillary tube.
19. Derive an expression for the excess pressure inside a curved surface and discuss
the different special cases.
20. Describe Jaeger's method of studying the variation of surface tension of water
with temperature.
Point out the advantages and disadvantages of the method.
21. Explain Doppler effect.
Find an expression for the change in frequency of a note when both the source of
sound and the observer are in relative motion.
22. Discuss the salient features associated with good acoustics of an auditorium.