Assertion : A wheel moving down a perfectly frictionless inclined plane will undergo slipping (not rolling motion)
Reason : For perfect rolling motion, work done Reason against friction is zero.

Explanation

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

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that a wheel moving down a perfectly frictionless inclined plane will undergo slipping and not rolling motion.
- On a frictionless surface, there is no frictional force to provide the necessary torque for rolling. Therefore, the wheel will not roll but will slip down the incline.

2. **Understanding the Reason**:
- The reason states that for perfect rolling motion, the work done against friction is zero.
- In perfect rolling motion, the point of contact between the wheel and the surface has zero relative velocity, which means that the wheel rolls without slipping. In this case, friction is necessary to prevent slipping and to allow for rolling.

3. **Analyzing the Conditions**:
- On a frictionless inclined plane, the coefficient of friction (μ) is zero. Thus, the frictional force is also zero.
- Since there is no friction, there is no torque generated about the center of the wheel, which means the wheel cannot roll and will instead slide down the incline.

4. **Conclusion**:
- The assertion is true: the wheel will slip down the incline due to the lack of friction.
- The reason is also true: in perfect rolling motion, the work done against friction is indeed zero. However, it does not explain why the wheel slips on a frictionless surface.
- Therefore, both the assertion and reason are true, but the reason does not adequately explain the assertion.

### Final Answer:
Both assertion and reason are true, but the reason is not the correct explanation for the assertion.