The electromagnetic radiations are in descending order of wavelength in the following sequence

Options

A. infra-red waves, radio waves X-rays, visible light rays
B. radio-waves, infra-red waves, visible, X-rays
C. radio waves, visible light, infra-red waves, X-rays
D. X-rays, visible light, infra-red wave, radiowaves

Answer

To determine the correct order of electromagnetic radiations in descending order of wavelength, we need to list the types of electromagnetic waves from the longest wavelength to the shortest wavelength. Here’s how we can do it step by step:

### Step-by-Step Solution:

1. **Identify the Types of Electromagnetic Waves**:
The main types of electromagnetic waves include:
- Radio Waves
- Microwaves
- Infrared (IR)
- Visible Light
- Ultraviolet (UV)
- X-rays
- Gamma Rays

2. **Understand Wavelength Order**:
In electromagnetic radiation, the wavelength decreases as we move from radio waves to gamma rays. Therefore, we need to arrange them starting from the longest wavelength to the shortest.

3. **Arrange the Waves in Descending Order of Wavelength**:
- **Longest Wavelength**: Radio Waves
- **Next**: Microwaves
- **Next**: Infrared (IR)
- **Next**: Visible Light
- **Next**: Ultraviolet (UV)
- **Next**: X-rays
- **Shortest Wavelength**: Gamma Rays

Thus, the correct order in descending wavelength is:
- Radio Waves > Microwaves > Infrared > Visible Light > Ultraviolet > X-rays > Gamma Rays

4. **Match with Given Options**:
Now, we need to compare this order with the options provided in the question.

5. **Select the Correct Option**:
After comparing the options, we find that the correct sequence is represented by Option B, which lists the waves in the correct descending order of wavelength.

### Final Answer:
The correct order of electromagnetic radiations in descending order of wavelength is:
**Radio Waves > Microwaves > Infrared > Visible Light > Ultraviolet > X-rays > Gamma Rays.**
The correct option is **Option B**.