GREY SCHOLARSHIP EXAMINATION.

CHEMISTRY.

Examiner PROFESSOR F. D. BROWN.

1. Describe Victor Meyer's method of determining the vapour density of a substance, and give an account of the more important results of the use of this method in Inorganic Chemistry.

2. In what way did the discovery by Gay Lussac of the law of gaseous volumes assist in establishing the atomic theory?

3. What properties of the elements argon and helium have been exactly determined, and how has this been accomplished?

4. Calculate the osmotic pressure at 50° C. of a sugar solution containing 50 grams of cane sugar (C12 H22 O11) per litre.

5. Describe Grotthus' explanation of electrolysis, and show clearly why it fails to account for the phenomena. Explain how the more recent views on the subject are more successful in this respect.

6. An organic salt yields on ignition a mixture of potassium and sodium carbonates. How would you estimate the proportion of sodium to potassium in this residue?

7. Give as complete an account as you can of the trioxides of nitrogen and of phosphorus.

GREY SCHOLARSHIP EXAMINATION.

ELECTRICITY AND

MAGNETISM.

Examiner: PROFESSOR F. D. BROWN.

1. Define the electrostatic C.G.S. unit of electric quantity. How would this unit be affected if the metre and kilogram were taken as units instead of the centimetre and gram?

2. What is a tube of force? Show that in a tube of force the product of the area of a cross-section of the tube by the mean value of the intensity of the field over the section must be constant throughout the tube.

3. A difference of potential V is maintained between two parallel plates separated from one another by a small distance d; one of the plates is large, and the other, which is relatively small, has an area a, and is furnished with a guard ring. Show that the force tending to draw the plates towards each other a V 2

is

4. Find the field strength at a point P at a distance d from the centre of a short magnet of moment M, (a) when P is on the prolongation of the axis, (b) when P is on a line passing through the centre of the magnet at right angles to the axis.

5. An iron bar, surrounded by a sufficient coil of wire, is subjected to the magnetizing action of a current in the coil. Explain exactly how you would find by experiment the approximate current strength required to bring about magnetic saturation in the bar.

GREY SCHOLARSHIP EXAMINATION.

. What is the meaning of the terms magneto-motive force," "magnetic reluctance," and "total magnetic flux"? How are these quantities related?

7. Explain how a rotating field can be produced by a combination of two or more alternating currents. How is such a field applied in the construction of certain types of electric motors?

GREY SCHOLARSHIP EXAMINATION.

HEAT, LIGHT, AND SOUND.

Examiner: PROFESSOR F. D. BROWN.

1. Why are the temperatures indicated by an air thermometer preferred, in accurate work, to those of a mercurial thermometer?

2. Explain Prevost's Theory of Exchanges, and show how relations between the emissive, absorptive, and reflective powers of substances may be deduced from the theory.

3. Show that the specific heat at constant pressure of a perfect gas must be of the specific heat at constant volume.

4. Define "Dispersive power," and show that it is possible, with suitable prisms, to construct a direct vision spectroscope.

5. When a beam of light falls normally upon one of the faces of a crystal of Iceland spar it emerges from the opposite and parallel face divided into two beams. Give a careful explana

tion of this fact.

6. Explain the production of coloured light by a thin plate of selenite placed between the polarizer and analyzer of a polariscope.

7. What theoretical relation exists between the loudness of a sound and the amplitude of the vibrations of the source of the sound. Explain how this relation may be verified experimentally.