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The Pamphlet Collection of Sir Robert Stout: Volume 50

University of New Zealand. — Physical Science. — Paper e (1). Heat

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University of New Zealand.

Physical Science.

Paper e (1). Heat.

1.Why is there a difference between the apparent specific heat of air and its true specific heat? How can the ratio of the two be experimentally obtained?
2.Assume the value of the above ratio to be 1·405: 1; assume also that the true specific heat of air is 0·23754 calories per gramme per degree (Centigrade); that the coefficient of expansion of air by heat is 0·003667 per degree; and that its density is 0·00129. From these data show how to calculate the mechanical equivalent of heat. (N.B. The calorie is the amount of heat required to warm one gramme of water one degree of the Centigrade scale.)
3.Assume 1 centimetre = 0·3937 inch; 1 gramme =15·432 grains; acceleration of gravity at Manchester =981·3 (centimetres per second per second). From these data calculate the value of Joule's equivalent in ergs per calorie taking as your basis Joule's statement that the heat required to warm 1 pound of water 1 degree Fahrenheit is mechanically equivalent to 773·65 foot-pounds.page 2
4.Describe De Senarmont's method of investigating the thermal conductivity of crystals, and briefly recount his results.
5.Give the calculations necessary to apply in deducing the specific heat of a substance from experiments made in using an ice-calorimeter. Describe the ice-calorimeter of Lavoisier and also that of Bunsen.
6.Give a sketch of the kinetic theory of gases.
7.Explain by the kinetic theory of gases:—
(a)the action of Crookes's radiometer.
(b)the cooling effect of a current of air.
(c)the "black plane" seen surrounding hot bodies when brightly illuminated.
(d)why a drop of cold water dropped upon a red hot silver plate runs about over the surface of the latter without touching it and with a visible space between.
8.What is an adiabatic? What is an isothermal? Are the conditions presupposed in the use of these terms in the theory of the heat-engine ever realised? If not, why?
9.Suppose a line A B to be drawn on a pressure-volume diagram, and through A and B respectively two adiabatics are drawn and continued indefinitely in the positive direction relatively to the volume-axis; show that the area enclosed between A B and these adiabatics measures the heat imparted or withdrawn during the operation which is represented by the line A B. What is the rule for signs in such operations?