A: If a bar magnet is cut into two equal halves then magnetic dipole moment of each part is half that of the original magnet.
R: magnetic dipole moment is the product of pole strength and magnetic length.

Options

A. If both Assertion & Reason are the true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reson is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false, then mark (3)
D. If both Assertion and Reason are false statements, then mark (4)

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided.

**Step 1: Understanding the Assertion (A)**
The assertion states that if a bar magnet is cut into two equal halves, then the magnetic dipole moment of each part is half that of the original magnet.

**Step 2: Understanding the Magnetic Dipole Moment**
The magnetic dipole moment (μ) of a bar magnet is given by the formula:
\[ \mu = m \cdot L \]
where \( m \) is the pole strength and \( L \) is the length of the magnet.

**Step 3: Cutting the Magnet**
When the bar magnet is cut into two equal halves, the length of each half becomes:
\[ L' = \frac{L}{2} \]
The pole strength \( m \) remains the same for each half.

**Step 4: Calculating the Magnetic Dipole Moment of Each Half**
For each half of the magnet, the magnetic dipole moment \( \mu' \) can be calculated as:
\[ \mu' = m \cdot L' = m \cdot \left(\frac{L}{2}\right) = \frac{m \cdot L}{2} = \frac{\mu}{2} \]
Thus, the magnetic dipole moment of each half is indeed half that of the original magnet.

**Step 5: Understanding the Reason (R)**
The reason states that the magnetic dipole moment is the product of pole strength and magnetic length. This statement is correct as it accurately describes the formula for magnetic dipole moment.

**Step 6: Conclusion**
Both the assertion and the reason are correct, and the reason correctly explains the assertion. Therefore, the answer to the question is that both the assertion and the reason are true, and the reason provides a correct explanation for the assertion.

### Final Answer:
Both the assertion (A) and the reason (R) are correct, and the reason explains the assertion.

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