E.—la.

7. Explain the principle of the pendulum. How may the pendulum be used to calculate the value of gl If a pendulum 392 inches long ticks seconds—that is, its period is 2 seconds —find g. [Take it as equal to -\ 2 -.] 8. One end of a uniform rod is attached to a hinge, and the other is supported by a string attached to the extremity of the rod and inclined to the horizontal at the same angle (45°) as the rod is. If Wbe the weight of the rod, find the amount and the direction of the strain on the hinge. 9. Describe the construction and use of the mercurial barometer. When the mercurial barometer stands at 29-5 inches find the pressure on a square yard. (The specific gravity of mercury is 13-6). Also find the height to which a common pump can lift water when the mercurial barometer stands at 28 inches. 10. State Boyle's law, and describe experiments to prove it. A cylindrical vessel the capacity of which is 1,200 cubic feet, open at one end, is forced under water until the surface of the water within it is 68 feet below the surface of the water in whi.ch it is immersed. Find the volume of air in the vessel when the mercurial barometer stands at 30 inches.

Physics. — For Glass D. Time allowed : Three hours. 1. Explain any method whereby you could ascertain the frequency of vibration of a tuningfork. 2. How would you arrange an experiment to show the relation between the pitch of a note and the length and tension of the string producing the note? 3. It is often stated that light travels in straight lines. Can the accuracy of this statement be tested experimentally '? Do you regard the statement as absolutely correct ?if not, how would you modify it ? 4. Describe two experiments which illustrate the fact that white light is not homogeneous. 5. Distinguish between conduction, convection, and radiation of heat. How do you explain the fact that a thermometer with a blackened bulb indicates a different temperature when exposed to the sun's rays from that which a common thermometer would indicate ? 6. Define the terms " coefficient of linear expansion" and "latent heat of fusion." How would you determine the coefficient of linear expansion of copper ? A brass cyclinder whose volume is 1 litre and diameter 8 centimetres at 0° C. is heated to 100°. If the coefficient of linear expansion of brass is 0-00002, what is the new volume and diameter of the cylinder? 7. Explain clearly the construction and mode of action of the gold-leaf electroscope, and of the Leyden jar. 8. The two ends of a small coil of insulated wire are passed through a large flat cork and soldered respectively to a plate of zinc and to a plate of copper, and the apparatus is then floated with the plates downwards in a basin of dilute sulphuric acid: what position relative to the magnetic meridian would you expect the coil to take up ? Give reasons for your answer.

Sound, Light, Heat. — For Civil Service Junior. Time allowed : Three hours. 1. Explain clearly any method whereby the velocity of sound in air and in hydrogen may be compared. What effect does a rise of temperature produce on the velocity of sound in air ? 2. In what respects may musical sounds differ from one another ? Explain these differences. 3. Describe two methods whereby the intensity of the illumination from two sources of light may be compared. A standard candle and a gas flame of nine-candle power are placed 10 feet apart, and a paper spotted with oil is placed between them in such a position that the grease spot becomes invisible. What is the distance of the paper from the gas flame? 4. State the laws of the reflection of light. How may they be applied to the deduction of the position of the principal focus of a spherical concave mirror? 5. Explain the meanings of the terms " refractive index " and " critical angle." Show that from a measurement of the critical angle the refractive index may be ascertained at once. 6. Two metals have specific gravities of 9-8 and 10 at 0° C. The coefficient of linear expansion of the former is 0-00003, of the latter 0-00001. At what temperature will the metals have the same density ? . 7. Define the terms unit quantity of heat, specific heat, latent heat of fusion. How would you attempt to determine the latent heat of vaporisation of water ?

Magnetism and Electricity. — For Civil Service Junior. Time allowed : Three hours. 1. Describe and explain the behaviour of a dipping-needle as the frame which supports it is turned round a vertical axis. What do you understand by the magnetic meridian at a given place ? 2. Mention the various methods whereby a steel bar may be magnetized and demagnetized. 3. State the laws of electrical attraction. How can they be shown to be true? 4. What is an electroscope ? Describe a convenient form of electroscope, and explain how you would use it to determine the sign of the electrification of a charged conductor. _5. What properties are observed in a wire through which an electric current is flowing ? Which of these properties are made use of in the practical measurement of current ? 6. Describe the construction of the Daniell cell and the Leclanche cell, and indicate the advantages and disadvantages of each. 7. Give a short account of the phenomenon known as electrolysis.

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