Out of the following, choose the ray which does not travel with the velicty of light

Options

A. X-ray
B. Microwave
C. `gamma` -rays
D. `beta`-rays

Answer

To solve the question of which ray does not travel with the velocity of light, we will analyze each option provided:

1. **Identify the types of rays:**
- **X-rays**: These are a form of electromagnetic radiation and travel at the speed of light (approximately \(3 \times 10^8\) m/s).
- **Microwaves**: These are also electromagnetic waves and travel at the speed of light.
- **Gamma Rays**: These are high-energy electromagnetic waves and, like X-rays and microwaves, travel at the speed of light.
- **Beta Rays**: These are not electromagnetic waves; they are streams of electrons or positrons emitted from radioactive decay. Beta rays do not necessarily travel at the speed of light.

2. **Determine which ray does not travel at the speed of light:**
- Since X-rays, microwaves, and gamma rays are all forms of electromagnetic radiation, they travel at the speed of light.
- Beta rays, being charged particles, do not travel at the speed of light. Their speed can vary depending on their energy but is always less than the speed of light.

3. **Conclusion:**
- The ray that does not travel with the velocity of light is **Beta Rays**.

Therefore, the correct answer is **Option 4: Beta Rays**.