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9. Gases are often dried and purified by passing
them through bottles containing successively solid caustic potash and strong sulphuric acid ? What would happen if you tried this method of drying the following gases—(1) ammonia, (2) carbon dioxide ?
10. What is a hydrocarbon ? Mention two or three
examples, and give an account of what occurs when they are burnt in the air.
The Board of Examiners.
Candidates are requested to answer the questions on
Dynamics, and on one but not more than one of the three subjects-Heat, Sound and Light, Electricity and Magnetism.
1. The ends of a uniform rod rest on two supports
which are 8 feet apart. The rod is in a horizontal position, and its weight is 6 lbs. From a point in it distant 3 feet from one of the points of support a weight of 24 lbs. is suspended.
Find the pressure on each support.
2. Of two bodies, one has a mass of 2 cwt. and moves
at the rate of 3 feet per second; the other has a mass of 42 lbs., and moves at the rate of 240 yards in a minute.
Compare the momenta of the bodies.
3. A tube filled with water is inverted with its open
end in water, no air having got in. The top of the tube is 16 feet above the surface of the water. If the water barometer stands at 34 feet, what is the pressure in pounds per square foot at a point on the top of the tube? (Take 1,000 ounces as the weight of a cubic foot of water.)
4. The specific gravity of lead is 11.4, that of cork is
0.24. What weight of lead will make 5 lbs. of cork just float in water?
5. A man weighing 147 lbs. puts on his back a weight
of 92 lbs., and carries it up a ladder to the height of 42 feet. How many foot-pounds of work does he do altogether, and what part of the work is done usefully?
6. Give in foot-pounds the energy of a train of 120
tons in weight, moving with a velocity of 45 miles per hour. Take g = 32, and use English,
. not French measures, in making the necessary calculations.
1. Explain what you mean by saying that the coeffi
cient of linear expansion of cast iron is 0.00001.
A cast-iron tube is 10 feet long in winter when the thermometer is at freezing point. Find its length in summer when the thermometer is 30° C.
2. Describe the experiment by which Leslie showed
that water can be frozen by its own evaporation.
3. State the effect on the volume of a given mass of
air of altering its temperature without altering its pressure; and also the effect on its pressure of altering its temperature without altering its volume.
4. Distinguish between the meanings of the terms
evaporation and ebullition; and state the laws of ebullition.
5. A vessel containing water is heated by a gas jet,
and a thermometer placed in the water rises to 100° C. when the water begins to boil. Why does not the thermometer continue to rise ? What becomes of the heat which is apparently lost?
6. What is meant by specific heat ?
15 lbs. of copper at 80° C. are put into 18 lbs. of water at 42 c. Assuming that the specific heat of water is 101 times that of copper, and that the operation is conducted without the loss of any heat, what will be the temperature of the water?
ELECTRICITY AND MAGNETISM. 1. Give a definition of the term unit of electricity;
and calculate at what distance 5 units of positive electricity will attract 6 units of negative elec
tricity with a force of 1.2 units. 2. Describe and explain the action of the gold-leaf
3. Why does electricity manifest itself only on the
surface of conductors; and what prevents its escape
from the surface ?
4. A partially charged body is at a considerable dis
tance from an insulated conductor. What will happen (1) if the charge be gradually increased ?
(2) if the distance be gradually diminished ? 5. State the law which connects the heating effect
produced by the discharge of a jar, with the quantity of electricity and the surface of the jar.
There are two jars whose surfaces are proportional to the numbers 8 and 9. Their charges are proportional to the numbers 5 and 6. If the heating effect produced by the discharge of the first be 100, what is the heating effect produced
by the discharge of the second ? 6. What is a solenoid ? In what respects does a
solenoid resemble a magnet ?
SOUND AND LIGHT. 1. Explain why sound travels easily with the wind,
and with difficulty against it. 2. How may it be shown that sound is not propagated
in vacuo? 3. Describe the construction and action of an organ.
pipe. 4. Briefly describe the optical portions of the human
eye; and point out the resemblance between the
eye and a camera obscura. 5. Describe Fizeau's method of finding the velocity of
light. 6. Does white light transmitted through a piece of
coloured glass acquire colour from the glass ? If not, what really does happen, and why?
The Board of Examiners. 1. Explain and illustrate the following statement:
“These observations might lead to the conclusion that it is the mind which directly governs the muscles, but a little further enquiry will
show that such is not the case.” 2. State what you know about the arterial circulation
and the functions of the arteries. 3. Comment on the chief conditions which hasten or
retard the coagulation of the blood. 4. Describe the forces of inspiration and expiration,
and illustrate your answer by rough diagrams. 5. Describe the structure of the kidneys, and illustrate
your answer by rough diagrams. 6. State what you know concerning the physiological
value and mode of digestion of proteid food. 7. Explain how voice is modulated into speech. 8. Describe the structure and arrangement of the parts
of the eye in front of the vitreous humour.
The Board of Examiners.
answers must be illustrated by rough sketches. 1. What are the different modifications of leaves
present on a flowering plant ? Give some description of them in any one plant.