Assertion : The work done during a round trip is always zero. Reason : No force is required to move a body in its round trip.

Options

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

Answer

To analyze the assertion and reason provided in the question, we will break down the concepts of work done in a round trip and the forces involved in circular motion.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that "the work done during a round trip is always zero."
- To evaluate this, we need to consider what a round trip entails. In a round trip, an object returns to its initial position after traveling a certain distance.

2. **Work Done Concept**:
- Work done (W) is defined as the product of the force (F) applied on an object and the displacement (d) in the direction of the force:
\[ W = F \cdot d \cdot \cos(\theta) \]
- If the object returns to its starting point, the net displacement is zero, which suggests that the total work done could be zero. However, this does not account for forces acting on the object during the trip.

3. **Analyzing Forces During the Trip**:
- When an object moves in a circular path, it experiences centripetal force directed towards the center of the circle. If there is friction, it acts in the opposite direction to the motion, doing negative work.
- Even if the object returns to its starting point, the work done against friction (if present) is not zero.

4. **Conclusion on the Assertion**:
- Therefore, the assertion that "the work done during a round trip is always zero" is **false** because, in the presence of friction or any other opposing force, work is done against these forces.

5. **Understanding the Reason**:
- The reason states that "no force is required to move a body in its round trip."
- This is misleading because, in circular motion, a centripetal force is necessary to keep the object moving in a circle. Additionally, if there is friction, a force is needed to overcome it.

6. **Conclusion on the Reason**:
- Hence, the reason is also **false** because forces (like centripetal force and friction) are indeed required to maintain motion in a round trip.

### Final Conclusion:
Both the assertion and the reason are false.