Question

Part 2: Logical Reasoning Briefly write the explanation for the following statements with valid reasons: • Viscosity of liquid decreases with increase in temperature • Density of compressible fluids do not remain constant. • Rise or fall of the liquid occurs in the capillary tube. • Gauge pressure is zero when the water is flowing out of the nozzle. • Mercury is commonly used as a manometer liquid.

Answer 1

• Viscosity of liquid decreases with increase in temperature. Explanation: 1 In case of liquids , viscosity is mainly due to conesive forces between the molecules. (2) As we increase temperature, cohesive forces between molecules decreases hence viscosity decreases. Density of compressible fluids do not remain constant. Explanation: (1) compressible fruich are those fluids whose density does not remain constant. (2) when we apply small pressure on such a substance, it causes large change in its .. volume hence it's density varies. (3) These fluids are highly compressible hence its I density do not remain constant. - Rise or fall of liquid occurs in the capillardy tube. Explanation: (1) The phenomenon of rise or fall of liquid inside a capillary tube when it is held vertical is called capillarity. (2) . It is mainly due to surface tension. - (3) In case of mercury, there is fall of liquid - in capillary tube, due to obtuse angle of contact.

Gauge pressure is zero when the water is flowing out of the nozzle. Explanation (1) Gauge pressure is the pressure which is measured with respect to atmospheric pressure. (2) snice water coming out of hozzle is at atmospheric pressure hence gauge pressure of water is zero. - Mercury is commonly used as manometer lig Explanation a It is used because due to its high density, it can measure high pressure by balancing a. column of liquid mercury with small reading. (2) It has low vapour pressure and works on all wide range of temperature. (3) well defined menti meniscus is formed when we ese mercury.