A laboratory assistant fills a glass flask completely with glycerine at and seals it…
PHYSICS · Subjective · CBSE · Physics · Thermal Properties of Matter · Thermal Properties of Matter
Problem
A laboratory assistant fills a glass flask completely with glycerine at 20∘C and seals it with a tight-fitting stopper. After some time the temperature in the room rises slowly to 35∘C. No glycerine is seen to leak out and yet, on removing the stopper, the liquid level is found to have dropped slightly.
(i) Distinguish between the real and the apparent expansion of a liquid with reference to this observation.
(ii) Explain qualitatively why the level of glycerine falls instead of rising when the temperature goes up.
(iii) If the real coefficient of cubical expansion of glycerine is greater than, equal to, or less than that of glass, state in each case what would be observed for the liquid level on heating and give a brief reason.