Short Answer TypeExplain the following:
(i) Drops of liquid assume a spherical shape.
(ii) The level of mercury in a capillary tube is lower than the level outside when a capillary tube is inserted in mercury.
(i) The spherical shape of drops: Surface tension accounts for the spherical shape of liquid drops. The effect of the surface tension is to decrease the surface area of the liquid to a minimum. Hence, liquid drops become spherical because a sphere has a minimum surface area for a given volume.
(ii) Fall of the mercury level in a capillary tube. This is because the force of attraction between the mercury molecules (cohesive forces) is greater than the adhesive forces between mercury and glass. This induces mercury to detach from the surface of the glass and level of the mercury goes down in the capillary tube.
Liquid that wets glass rises in a capillary tube or oil rises in the wick of an oil Jamp. Explain.
Long Answer TypeExplain the following:
(i) The boiling point of water (373 K) is abnormally high when compared to that of H2S (211·2K).
(ii) Liquids like ether and acetone are kept in cool places.
(iii) Tea or coffee is sipped from a saucer when it is quite hot.
Explain briefly the term viscosity. Define coefficient of viscosity. What are its units?
Short Answer TypeWhich one in each of the following pairs is more viscous?
(i) Coconut oil, castor oil
(ii) glyercine, kerosene
(iii) soft drink, aerated water (soda water)?
Long Answer TypeWhat is the effect of temperature on:
(i) density
(ii) surface tension
(iii) viscosity
(iv) the vapour pressure of a liquid?
Short Answer TypeWhat is the effect of pressure on:
(i) volume
(ii) boiling point
(iii) viscosity of a liquid?
Long Answer TypeShort Answer Type
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