which of the following statements is not true ?

Options

A. Paramagnetic substances are weakly attracted by magnetic field
B. Ferromagnetic substance cannot be magnetised permanently
C. the domains in antiferromagnetic substance are oppositely oriented with respect to each other
D. Paring of electrons cancels their magnetic moment in the diamagnetic substances

Explanation

To determine which of the following statements is not true, we will analyze each statement one by one.

### Step 1: Analyze the first statement
**Statement 1:** Paramagnetic substances are weakly attracted by a magnetic field.

- **Explanation:** This statement is true. Paramagnetic substances have unpaired electrons, which means they have a net magnetic moment. When placed in a magnetic field, they align with the field and are weakly attracted.

### Step 2: Analyze the second statement
**Statement 2:** Ferromagnetic substances cannot be magnetized permanently.

- **Explanation:** This statement is false. Ferromagnetic substances can be magnetized permanently. They have regions called magnetic domains that can remain aligned even after the external magnetic field is removed, allowing them to retain their magnetism.

### Step 3: Analyze the third statement
**Statement 3:** The domains in antiferromagnetic substances are oppositely oriented with respect to each other.

- **Explanation:** This statement is true. In antiferromagnetic materials, the magnetic moments of adjacent atoms or ions are aligned in opposite directions, effectively canceling each other out.

### Step 4: Analyze the fourth statement
**Statement 4:** Pairing of electrons cancels their magnetic moment in diamagnetic substances.

- **Explanation:** This statement is also true. In diamagnetic substances, all electrons are paired, which results in no net magnetic moment. When exposed to a magnetic field, these substances are weakly repelled.

### Conclusion
Based on the analysis, the statement that is not true is:

**Answer:** Statement 2: Ferromagnetic substances cannot be magnetized permanently.

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