Question

Smaller drops of liquid resist deforming forces better than the larger drops. Excess pressure inside a drop is directly proportional to its surface area.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (C)

If assertion is true but reason is false

Answer 2

Also excess pressure inside a bubble is $P=\frac{4 T}{R}$ where $R$ is radius of bubble. Since excess pressure is inversely proportional to radius, hence excess pressure inside a smaller drop is large as compared to larger drop due to which smaller drop resists deforming forces better than a larger drop Also $P=\frac{4 T}{R}$ $P \propto \frac{1}{\Delta A}$ Also $P=\frac{4 T}{R}=\frac{4 W}{R \cdot \Delta A}$ $\left(\because T=\frac{W}{\Delta A}\right)$ $\Rightarrow P \propto \frac{1}{\Delta A}$ Hence, excess pressure is inversely proportional to surface area.