4. Develop Bernouilli's theorem and apply it to explain the use of a Pitot tube for measuring the velocity of a ship. 5. Discuss the structure of an atom with reference to the following points: (a) evidence for the existence of a common constituent, (b) positive rays. B. Write on any four of the following questions. 6. (a) Explain why the specific heat of a gas at constant pressure is greater than at constant volume. (b) Establish the relation Cp=Cv+R/J. 7. (a) What is the significance of the term y in the adiabatic gas law pv Y = constant? (b) Air at to a volume 2v. 20°C. suddenly expands from a volume v Find the fall in temperature. for air y=1.4, 8. (a) State the first and second laws of thermodynamics. (b) What do you understand by the thermal efficiency of a steam engine? (c) Determine the theoretical efficiency of a steam engine whose boiler is at 150°C. and its condenser 40°C. 9. (a) Describe Kelvin and Joule's porous plug experiment and, in general terms, state their results. (b) Hence outline a method of liquifying a so-called permanent gas. 10. Describe fully the phenomena attending the approach and passage of a tropical cyclone. EXPERIMENTAL HONOUR PHYSICS II. (ARTS). A. Candidates will write on only three questions in part A. 1. (a) Describe a method of measuring the resistance of a D'Arsonval galvanometer. (b) A galvanometer of resistance 110 ohms has a sensibility of 10- ampere. If you were provided with two standard resistance boxes, one reading from .1 ohm to 25 ohms, the other from 1 to 10,000 ohms, work out how you would use the galvanometer (1) as a milliammeter, so that 1 cm. deflection .05 ampere, (2) as a millivoltmeter, so that 1 cm. deflection = .05 volt. 2. You are provided with a good ammeter, a variable rheostat, a storage battery, two 5000 ohms standard resistance boxes, a standard Weston cell, a straight uniform wire 100 cms. long, a high resistance, a galvanometer, and a few dry cells. How would you use the above apparatus to measure the resistance of a rod of metal? 3. (a) The same galvanometer may be used to measure current or ballistically. How is this possible? (b) In the case of a condenser discharge, what is the difference in the readings with damping coil on and off the galvanometer? (c) Outline briefly a method of using a ballistic galvanometer to measure the strength of an unknown magnetic field. 4. The following sets of readings were taken with a tangent galvanometer for two current values: No. of turns Average deflection 1235700 9 I, 18° 31° 40° 55° 45' 63° 15' 68° 45' ངའ 13° 26° 35° 50° 59° 67° 30' (a) Show graphically that the tangent of the angle is proportional to the number of turns. (b) Use each graph to find a single average value of the corresponding current. Radius of coil 10 cm. H=0.19. B. Write on only three of the following questions. 5. (a) What is meant by "logarithmic decrement"? Describe a practical method of finding its value. (b) Describe an experimental method of determining the resultant path of a particle subject to two simple harmonic motions in lines perpendicular to each other. 6. Describe any two ways of finding experimentally the moment of inertia of an irregular body, such as a horseshoe, about an axis through its centre of mass and perpendicular to the plane of the horseshoe. Discuss the accuracy of the results you would obtain in each case. equal to T M Show how to test this experimentally. Explain why the observed and calculated values agree better in the case of a chain than in that of a light rope. (b) Explain the use of a micrometer eye-piece. 8. Name any two ways of measuring the wave length of light. Describe one in detail and discuss the accuracy of the value which you would obtain. |