Assertion: Limiting friction depends on the degree of smoothness.
Reason : Kinetic friction is less than limiting friction.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If oth 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

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

### Step 1: Understand the Assertion
The assertion states that "Limiting friction depends on the degree of smoothness."

- Limiting friction is the maximum frictional force that must be overcome to start moving an object at rest.
- The degree of smoothness of a surface affects how much friction is present.
- Smooth surfaces have fewer irregularities, leading to lower limiting friction, while rough surfaces have more irregularities, leading to higher limiting friction.

### Step 2: Understand the Reason
The reason states that "Kinetic friction is less than limiting friction."

- Kinetic friction is the frictional force acting on an object that is already in motion.
- It is generally true that kinetic friction is less than limiting friction because once an object is in motion, it encounters less resistance than when it is at rest.

### Step 3: Evaluate the Relationship
Now we need to evaluate whether the reason correctly explains the assertion.

- While both statements are true, the reason does not explain why limiting friction depends on the degree of smoothness.
- The assertion is about how surface smoothness affects limiting friction, while the reason is about the comparison between kinetic and limiting friction.

### Conclusion
The assertion is true, and the reason is also true, but the reason does not provide a correct explanation for the assertion. Thus, the correct answer is that the assertion is true, the reason is true, but the reason does not explain the assertion.

### Final Answer
- The assertion is true.
- The reason is true.
- The reason does not explain the assertion.