Point out the wrong statement about the magnetic properties of soft iron and steel.

Options

A. Retentivity of soft iron is more than retentivity of steel.
B. Coercivity of soft iron is less than coercivity of steel..
C. Area of B-H loop in soft iron is smaller than the area of B-H loop .for steel.
D. Area of B-H in soft iron is greater than the area of 8-H loop .for steel.

Explanation

To solve the question regarding the magnetic properties of soft iron and steel, we need to analyze the properties of both materials based on their BH loops. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the BH Loop
The BH loop (magnetic hysteresis loop) represents the relationship between magnetic field strength (H) and magnetic flux density (B) for a material. The area within the loop indicates the energy loss during magnetization and demagnetization.

### Step 2: Identify Key Properties
From the BH loop, we can derive several important properties:
1. **Retentivity**: The ability of a material to retain magnetization after the external magnetic field is removed.
2. **Coercivity**: The measure of the resistance of a ferromagnetic material to becoming demagnetized.
3. **Area of the BH Loop**: The area under the BH loop indicates the energy loss per cycle of magnetization.

### Step 3: Analyze Soft Iron and Steel
- **Retentivity**: Soft iron has a higher retentivity than steel. Therefore, the statement "retentivity of soft iron is more than retentivity of steel" is correct.
- **Coercivity**: Soft iron has a lower coercivity than steel. Thus, the statement "coercivity of soft iron is less than coercivity of steel" is also correct.
- **Area of BH Loop**: The area of the BH loop for steel is greater than that for soft iron, indicating that steel has more energy loss during magnetization. Therefore, the statement "area of BH loop in soft iron is smaller than the area of BH loop for steel" is correct.

### Step 4: Identify the Wrong Statement
The question asks for the wrong statement. The statement "area of BH loop in soft iron is greater than the area of BH loop for steel" contradicts our analysis, as we established that the area for steel is greater than that for soft iron.

### Conclusion
The wrong statement is: "The area of BH loop in soft iron is greater than the area of BH loop for steel."

### Final Answer
The correct answer is option D.

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