Identify the mismatched pair.
`{:(,"Hard magnet","Alnico"),(,"Soft magnet","Soft iron"),(,"Bar magnet","Equivalent solenoid"),(,"Electromagnet","Loud speaker"):}`

Options

A. `{:(,"Hard magnet","Alnico"):}`
B. `{:(,"Soft magnet","Soft iron"):}`
C. `{:(,"Bar magnet","Equivalent solenoid"):}`
D. `{:(,"Electromagnet","Loud speaker"):}`

Answer

To identify the mismatched pair from the given options, we will analyze each pair one by one.

1. **Hard Magnet - Alnico**:
- Hard magnets are materials that retain their magnetism after being magnetized. Alnico is an alloy made primarily of aluminum, nickel, and cobalt, and is known for its strong magnetic properties. Therefore, this pair is correctly matched.

2. **Soft Magnet - Soft Iron**:
- Soft magnets are materials that have low retentivity and high permeability, meaning they can be easily magnetized and demagnetized. Soft iron is a classic example of a soft magnetic material. Thus, this pair is also correctly matched.

3. **Bar Magnet - Equivalent Solenoid**:
- A bar magnet can be considered equivalent to a solenoid in terms of their magnetic field characteristics. Both have similar magnetic moments and can produce similar magnetic fields. Hence, this pair is correctly matched.

4. **Electromagnet - Loud Speaker**:
- A loudspeaker does utilize an electromagnet to convert electrical energy into sound. The electromagnet in a loudspeaker interacts with a permanent magnet to produce sound. Thus, this pair is correctly matched as well.

After analyzing all the pairs, we find that the only mismatched pair is:

**Answer**: Hard magnet - Alnico (This is the mismatched pair).

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