Assertion: Magnetic moment of a current loop does not depend on the shape of the loop.
Reason: Magnetic moment is a vector quantity and its direction is perpendicular to its plane.

Options

A. If both assertion and reason are correct and reason is a correct explanation of the assertion .
B. If both assertion and reason are correct but reason is not the correct explanation of assertion.
C. If assertion is correct but reason is incorrect.
D. If assertion is incorrect but reason is correct.

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 the magnetic moment of a current loop does not depend on the shape of the loop. The magnetic moment (M) of a current loop is given by the formula:
\[ M = n \cdot I \cdot A \]
where:
- \( n \) is the number of turns in the loop,
- \( I \) is the current flowing through the loop,
- \( A \) is the area of the loop.

### Step 2: Analyze the Area
The area \( A \) is a scalar quantity that depends on the size of the loop, but not its shape. For instance, a triangle and a circle can have the same area, but their shapes are different. Thus, the magnetic moment depends on the area, which does not vary with the shape of the loop.

### Step 3: Understand the Reason
The reason states that the magnetic moment is a vector quantity and its direction is perpendicular to its plane. This is indeed correct. The direction of the magnetic moment is determined by the right-hand rule, where the thumb points in the direction of the magnetic moment when the fingers curl in the direction of the current.

### Step 4: Conclusion
Both the assertion and the reason are correct statements. However, the reason does not explain the assertion correctly. The assertion focuses on the independence of the magnetic moment from the shape of the loop, while the reason discusses the vector nature and direction of the magnetic moment.

### Final Answer
Thus, the correct choice is:
**B: Both assertion and reason are correct, but the reason is not the correct explanation of the assertion.**

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