Assertion :When height of a tube is less than liquid rise int eh capillary tube, the liquid does not overflow.
Reason : Product of radius of meniscus and height of liquid in the capilliary tube always remains constant.

Options

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 and reason is false.
D. If both assertion and reason are false.

Explanation

To solve the given question, we need to analyze both the assertion and the reason provided.

### Step 1: Understand the Assertion
The assertion states that when the height of a tube is less than the liquid rise in the capillary tube, the liquid does not overflow. This implies that if the tube is shorter than the height to which the liquid would naturally rise due to capillary action, the liquid will not spill out of the tube.

### Step 2: Understand the Reason
The reason states that the product of the radius of the meniscus and the height of the liquid in the capillary tube always remains constant. This is based on the relationship derived from the principles of capillarity, which can be expressed as:
\[ h \cdot R = \frac{2S}{\rho g} \]
where:
- \( h \) is the height of the liquid column,
- \( R \) is the radius of the meniscus,
- \( S \) is the surface tension of the liquid,
- \( \rho \) is the density of the liquid,
- \( g \) is the acceleration due to gravity.

### Step 3: Analyze the Relationship
From the equation, we can see that if the height \( h \) of the liquid column decreases (for example, when the height of the tube is reduced), the radius \( R \) of the meniscus must increase to keep the product \( h \cdot R \) constant. This means that the liquid will adjust its meniscus shape to maintain equilibrium.

### Step 4: Conclusion
Since both the assertion and the reason are true, and the reason correctly explains the assertion, we conclude that:
- Both the assertion and reason are true.
- The reason is a correct explanation of the assertion.

### Final Answer
Both the assertion and reason are true, and the reason is the correct explanation for the assertion.

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