Calendar: 1873-1874 Page 560

560 APPLIED SCIENCES Five parallel lines are ruled at equal distances on glass plate explain why spectrum is formed when beam of light falls upon the glass plate after passing through slit which is parallel to the ruled lines show that the position of the spectrum depends on the number of ruled lines to the inch What is meant by saying that beam of light is plane- polarized What is the difference between plane-polarized and circularly-polarized light Describe some form of apparatus by which beam of plane-polarized light may be obtained and the plane in which it is polarized determined Give reasons for supposing the earth to be spherical Find approximately the height of mountain at the summit of which the dip of the horizon is 307 10 Account for the phases of the moon Explain why the amount of moonlight and the full moon's meridian altitude at any place on the earth is greatest in mid-winter at that place 11 State Kepler's Laws and point out their bearing on Newton's discovery of the principle of universal gravitation Explain how this principle enables us to account for the pheno- meoa of tides When may spring tides be expected 12 Explain the effect of parallax on the apparent position of the sun or of planet as seen from the earth's surface What phenomenon is most favourable for obtaining the sun's parallax The sun's parallax being 8"'57 and the earth's radius 000 miles determine the earth's distance from the sun and the error in the distance caused by an error of tenth of second in parallax ftjjUroStattcs anH tat FIRST YEAR Define fluid Prove from your definition that the pres- sure of fluid at rest upon any plane must be in direction perpendicular to the plane Find the pressure on rectangular plate 12 inches by when immersed in water so that its centre of gravity is at depth of 24 inches Define specific gravity Describe the different methods that