Which of the following are electromagnetic waves ?

Options

A. beeta-rays
B. Cathode rays
C. gamma-rays
D. Both (1) & (2)

Answer

To determine which of the following are electromagnetic waves, we need to understand the characteristics of electromagnetic waves and compare them with the options given.

### Step-by-step Solution:

1. **Definition of Electromagnetic Waves**:
- Electromagnetic waves (EM waves) are waves that consist of oscillating electric and magnetic fields. They do not require a medium to propagate and can travel through vacuum, air, or solid materials.

2. **Characteristics of EM Waves**:
- EM waves travel at the speed of light in a vacuum, which is approximately \(3 \times 10^8\) meters per second.
- The electric and magnetic fields in EM waves are perpendicular to each other and also perpendicular to the direction of wave propagation.
- EM waves include a variety of types, categorized in the electromagnetic spectrum, which includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

3. **Analyzing the Options**:
- **Option A: Beta Rays**: Beta rays are not electromagnetic waves; they are charged particles (electrons or positrons) emitted during radioactive decay.
- **Option B: Cathode Rays**: Cathode rays are also not electromagnetic waves; they are streams of electrons observed in vacuum tubes.
- **Option C: Gamma Rays**: Gamma rays are indeed part of the electromagnetic spectrum and are high-energy electromagnetic radiation.
- **Option D: Both 1 and 2**: This option is incorrect as both beta rays and cathode rays are not electromagnetic waves.

4. **Conclusion**:
- The only option that represents electromagnetic waves is **Option C: Gamma Rays**.

### Final Answer:
The correct answer is **Option C: Gamma Rays**.

---