Phys 114 -final 2002

(B. Sc. Biochemistry) First Semester 2002 Subject: Phys 114 (Physics)

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) Long Questions (Any three)

1.

2. 3. 4.

(3× ×14 = 42)

Find the amount of liquid coming out per second through a capillary tube of length l and internal radius r whose ends are kept at a pressure difference of p. Find the depth to which mercury falls in a capillary tube when an end of tube is dipped in mercury. Describe Wheatstone bridge. Obtain balance condition for the bridge with the help of Kirchoff’s law. State and explain Ampere’s theorem. Calculate magnetic field in a toroid using the theorem.

Group (B) Short Questions: (Any six)

(6× ×7 = 42)

1. What is radius of gyration? Explain in brief. 2. What is a pitot tube? Explain its working. 3. Explain why some liquid surfaces are concave and some are convex in shape? 4. In giving a patient a blood transfusion, the bottle is set up so that the level of blood is 1.3 m above the needle which has internal diameter of 0.36 mm amd length 3 cm. if 45 cm3 of blood passes through the needle in one minute, calculate the viscosity of the blood. Density of blood is 1.002 gm cm-3. 5. State Norton’s theorem. 6. Find the Thevenin’s equivalent circuit for the given circuit. R1 = 1 K

V = 20 V

R2 = 1 K

R3 = 1 K

7. Calculate electric potential energy at a point charge 1 C in the figure.

q1= +6µC

8 cm

q3= 1µC

4 cm q2= 4µC

8. Explain principle of an oscillator. Group (C) Very Short Questions: (Any eight)

1. Why detergents are used to wash clothes? 2. Why ends of a glass rod become rounded on heating? 3. Why a steel ball falling through long column of glycerin attains constant velocity? 4. A uniform rod of length 3 m is rotating about an axis passing through its midpoint and perpendicular to its length. What is its radius of gyration? 5. What is a couple? Give two such examples. 6. What do you mean by resonance in LC circuit? 7. State right hand thumb rule to find direction of magnetic field due to a straight conductor. 8. A vertical conductor carries 0.5A current. What is the magnetic field at a point at the distance 10 cm from the conductor? ( °= 4 X 10-7 Hm-1). 9. How does inductive reactance change with requency? 10. Draw the circuit diagram of a common emitter amplifier? 11. What are the electromagnetic waves? 12. Draw the circuit diagram of a common emitter amplifier.

(2× ×8 = 16)