Which of the following is not electromagnetic wave?

Options

A. X-rays
B. `beta`-rays
C. Cosmic rays
D. Both (2) & (3)

Answer

To determine which of the following is not an electromagnetic wave, we need to understand what constitutes an electromagnetic wave and analyze the given options.

### Step-by-Step Solution:

1. **Understanding Electromagnetic Waves**:
Electromagnetic waves are generated by the interaction of electric and magnetic fields. They do not require a medium to propagate and can travel through a vacuum.

2. **Identifying the Options**:
We need to evaluate the options provided. The question mentions beta rays, cosmic rays, and possibly other types of waves (not specified in the question).

3. **Analyzing Beta Rays**:
- Beta rays are emitted during radioactive decay and consist of electrons (or positrons).
- Since beta rays are charged particles, they can be deflected by magnetic fields.
- Because they are charged particles and not waves produced by the interaction of electric and magnetic fields, beta rays are **not** electromagnetic waves.

4. **Analyzing Cosmic Rays**:
- Cosmic rays are high-energy particles that originate from outer space.
- They consist of protons, atomic nuclei, and other subatomic particles.
- Similar to beta rays, cosmic rays do not involve the interaction of electric and magnetic fields to produce waves; hence, they are also **not** electromagnetic waves.

5. **Conclusion**:
Based on the analysis, both beta rays and cosmic rays are not electromagnetic waves. If the options included other types of waves (like radio waves, microwaves, etc.), those would be electromagnetic waves. Therefore, the answer to the question is that both beta rays and cosmic rays are not electromagnetic waves.

### Final Answer:
Beta rays and cosmic rays are not electromagnetic waves.

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