Phys 114-internal 2005

UNIVERSAL SCIENCE COLLEGE (B.Sc. Biochemistry)

Second Term Exam Subject: Physics (Phys 114) Date: - 12th Feb 2006

First Semester 2006

Full Marks: 100 Pass Marks: 45 Time: 3 Hours

Candidates are required to give their answers in their own words as far as practicable. The figure in the margin indicates full marks.

Group – A (Any Three)

(3 X 14=42)

1. Explain the concept of partial molal properties and chemical potential .Establish the Gibbs-Duhem equation and show that the chemical potential of constituents of solution are not independent of each other. 2. Describe the methods for measuring the distance and size of heavenly bodies from the earth. 3. Describe about shape of meniscus of liquid and angle of contact on the basis of different forces acting on interface with diagram. Also derive the expression of excess pressure developed inside liquid drop. 4. Describe about full wave bridge rectifier circuit and also about Hartley oscillator with neat diagram.

Group – B (Any Six)

(6 X 7=42)

1. What do you mean by double refraction or birefringence? Distinguish between the positive and negative crystal using concept of birefringence. 2. Write short note on smetic phases of liquid crystal. 3. Explain the different applications of the liquid crystal. 4. The first line in the hydrogen spectrum normally has a wave length of 6563 A0 . If in the spectrum of a star , this line is observed to have a wave length of 6565 A0 , what is the speed of recession of the star? 5. Show that the potential energy per unit area of liquid surface is equal to coefficient of surface tension. 6. The internal diameter of the glass tube of mercury barometer is 2mm.The barometer reads 74.45 cm of Hg. Find the correct reading of the barometer after allowing for the error due to surface tension. [Density of mercury, surface tension and its angle of contact are 13600kgm-3,3.5×101 Nm-1 and 135o respectively] 7. Explain about d.c. induction motor with its related terms. 8. Describe about common emitter amplifier with neat diagram.

Group –C (Any Eight)

(8 X 2=16)

1. What is the difference between terrestrial and jovian planets? 2. State three kepler’s laws of of planetary motion. 3. What is the ordered parameter? How does it distinguish the liquid crystal from solid and liquid? 4. What is the significance of Hubbles law? 5. What do you mean by freedericksz transition? 6. Why it is easier to wash clothes in warm water? 7. It is easier to spray water in which some soap is dissolved, why? 8. Why is it not possible to separate to pieces of paper joined by glue or gum? 9. What is filter circuit? 10. What are the characteristics of electromagnetic waves? 11. What are differences between oscillator and amplifier?