What is the usual name of magnets whose magnetism can be turned on or off as desired ?

Answer

To solve the question "What is the usual name of magnets whose magnetism can be turned on or off as desired?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question is asking for a specific type of magnet that can have its magnetic properties controlled or switched on and off.

2. **Identify the Type of Magnet**: There are different types of magnets, such as permanent magnets and temporary magnets. However, the type of magnet that can be controlled is different.

3. **Define the Key Concept**: The type of magnet that can have its magnetism turned on or off is known as an electromagnet. An electromagnet is created when an electric current flows through a coil of wire, often wrapped around a core material like iron.

4. **Explain the Mechanism**: When the switch is closed, and current flows through the wire, the iron core becomes magnetized, creating a magnetic field. When the switch is opened, the current stops, and the magnetism disappears.

5. **Conclude with the Answer**: Therefore, the usual name for magnets whose magnetism can be turned on or off is "Electromagnet".

### Final Answer:
The usual name of magnets whose magnetism can be turned on or off as desired is **Electromagnet**.

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