Given below are two statements:
Statement-I: The hot water flows faster than cold water.
Statement-II: Soap water has higher surface tension as compared to fresh water.
In the light of the above statements, choose the correct answer from the options given below:
Statement-I is false but Statement II is true
Statement-I is true but Statement II is false
Both Statement-I and Statement-II are true
Both Statement-I and Statement-II are false
Correct answer:B
Standard Method
Given: Two statements about flow of hot water and surface tension of soap water.
Find: Which option correctly identifies the truth values of Statement-I and Statement-II.
Statement-I is about viscosity. As the temperature of water increases, viscosity decreases. Therefore, hot water offers less resistance to flow than cold water, so it flows faster. Hence, Statement-I is true.
Statement-II is about surface tension. Adding soap to water reduces surface tension because soap acts as a surfactant and weakens the cohesive effect at the surface. Therefore, soap water does not have higher surface tension than fresh water. Hence, Statement-II is false.
So, the correct conclusion is: Statement-I is true but Statement-II is false.
Therefore, the correct option is B.
Statement-wise Analysis
Given:
Find: The correct option based on physical principles.
Analysis of Statement-I: Viscosity is the resistance offered by a fluid to flow. For liquids, viscosity generally decreases with increase in temperature. Hence, hot water has lower viscosity than cold water and therefore flows more easily. So, Statement-I is true.
Analysis of Statement-II: Surface tension is due to cohesive forces between liquid molecules. Soap reduces the surface tension of water by disturbing these cohesive forces. Therefore, soap water has lower surface tension than fresh water. So, Statement-II is false.
Checking the options:
Therefore, the correct option is B.
Confusing viscosity with speed of flow. Higher temperature lowers the viscosity of liquids like water, so hot water flows more easily. Do not assume all fluid properties increase with temperature.
Assuming soap increases surface tension because it changes the water surface. This is wrong because soap is a surfactant and reduces cohesive forces at the surface. Remember that soap lowers surface tension.
Get unlimited AI-adaptive practice, mastery tracking, and an AI tutor that explains every step — free to start.
