Question

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:

• A. Statement-I is false but Statement II is true
• B. Statement-I is true but Statement II is false
• C. Both Statement-I and Statement-II are true
• D. Both Statement-I and Statement-II are false

Hint:

Hot water flows faster than cold water due to its lower viscosity, and soap reduces the surface tension of water.

Answer 1

The Correct Option is B

To solve this question, we need to evaluate each statement individually in the context of standard physics principles.

Analysis of Statement-I: "The hot water flows faster than cold water." 

This statement deals with the viscosity of fluids. Viscosity is the measure of a fluid's resistance to flow. As the temperature of water increases, its viscosity decreases. Therefore, hot water has a lower viscosity than cold water, allowing it to flow more easily. Hence, Statement-I is true.

Analysis of Statement-II: "Soap water has higher surface tension as compared to fresh water."

Surface tension is the tendency of fluid surfaces to shrink into the minimum surface area possible and is caused by the attraction between the liquid molecules. Adding soap to water decreases its surface tension because soap molecules disrupt the cohesive forces between water molecules. Soap acts as a surfactant, which means it reduces the surface tension of water. Therefore, Statement-II is false.

Now, let's evaluate the options:

• Option 1: Statement-I is false but Statement-II is true. (Incorrect, as Statement-I is true and Statement-II is false.)
• Option 2: Statement-I is true but Statement-II is false. (Correct, as analysis showed this statement arrangement to be true.)
• Option 3: Both Statement-I and Statement-II are true. (Incorrect, as Statement-II is false.)
• Option 4: Both Statement-I and Statement-II are false. (Incorrect, as Statement-I is true.)

Based on the analysis, the correct answer is: Statement-I is true but Statement-II is false.

Answer 2

The solution involves analyzing each statement based on principles of physics.

Statement-I: "The hot water flows faster than cold water."

Explanation: This statement is related to viscosity. Viscosity is a measure of a fluid's resistance to deformation at a given rate. As temperature increases, the viscosity of liquids generally decreases, meaning they flow more easily. Hence, hot water has lower viscosity than cold water, allowing it to flow faster. Therefore, Statement-I is true.

Statement-II: "Soap water has higher surface tension as compared to fresh water."

Explanation: Surface tension arises due to cohesive forces between liquid molecules. When soap is added to water, it decreases the cohesive forces by disrupting the hydrogen bonds between water molecules. This results in decreased surface tension. Therefore, soap water has lower surface tension than fresh water, making Statement-II false.

Combining these analyses, the correct choice is that Statement-I is true but Statement-II is false.