The material suitable for making electromagnets should have

Options

A. High retentivity and high coercivity
B. Low retentivity and low coercivity
C. High retentivity and low coercivity
D. Low retentivity and high coercivity

Answer

To determine the material suitable for making electromagnets, we need to consider the properties of retentivity and coercivity. Here’s a step-by-step solution:

### Step 1: Understand Retentivity
- **Definition**: Retentivity is the ability of a magnetic material to retain magnetization after the external magnetic field is removed.
- **Importance for Electromagnets**: A material with high retentivity will hold onto its magnetic properties even after the current (which creates the magnetic field) is turned off. This is generally not desirable for electromagnets, as we want the magnetism to disappear when the current stops.

### Step 2: Understand Coercivity
- **Definition**: Coercivity is the measure of the resistance of a magnetic material to becoming demagnetized. It is the minimum magnetizing intensity required to demagnetize the material.
- **Importance for Electromagnets**: A material with low coercivity can be easily demagnetized, which is beneficial for electromagnets since we want the magnetism to be easily turned off when the current is stopped.

### Step 3: Combine the Concepts
- For a material to be suitable for making electromagnets, it should have:
- **High Retentivity**: This is actually not ideal for electromagnets since we want the magnetism to disappear when the current stops.
- **Low Coercivity**: This is ideal, as it allows for easy demagnetization.

### Step 4: Conclusion
- The best material for making electromagnets should have **low coercivity** and ideally low retentivity to ensure that it can be easily turned off when the current is removed.
- Therefore, the correct answer is that the material suitable for making electromagnets should have **high retentivity and low coercivity**.

### Final Answer
The material suitable for making electromagnets should have **high retentivity and low coercivity**.

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