Which one of the following groups of e.m. wave is/are in order of increasing frequency?

Options

A. microwaves, ultraviolet rays, X-rays
B. radiowaves, infrared radiation and visible light.
C. gamma rays , visible light, ulrtaviolet rays
D. gamma rays, ultraviolet rays, radio waves.

Explanation

To determine which group of electromagnetic (e.m.) waves is in order of increasing frequency, we need to understand the relationship between frequency and wavelength in the electromagnetic spectrum. The general order of electromagnetic waves from lowest frequency to highest frequency is as follows:

1. Radio Waves
2. Microwaves
3. Infrared (IR)
4. Visible Light
5. Ultraviolet (UV)
6. X-rays
7. Gamma Rays

### Step-by-Step Solution:

1. **Identify the Order of Electromagnetic Waves**:
- The electromagnetic spectrum is arranged in order of increasing frequency (or decreasing wavelength). The order is:
- Radio Waves < Microwaves < Infrared < Visible Light < Ultraviolet < X-rays < Gamma Rays.

2. **Analyze Each Group of Waves**:
- **Group 1**: Microwaves, Ultraviolet, X-rays
- Order: Microwaves (lowest frequency) < Ultraviolet < X-rays (highest frequency). This group is in the correct order of increasing frequency.
- **Group 2**: Radio Waves, Infrared, Visible Light
- Order: Radio Waves < Infrared < Visible Light. This group is also in the correct order of increasing frequency.
- **Group 3**: Gamma Rays, Visible Light, Ultraviolet
- Order: Gamma Rays (highest frequency) > Visible Light > Ultraviolet. This group is not in the correct order because it starts with the highest frequency.

3. **Conclusion**:
- The first and second groups are in the correct order of increasing frequency, while the third group is not. Therefore, the correct options are the first and second groups.

### Final Answer:
The groups of e.m. waves in order of increasing frequency are:
- Group 1: Microwaves, Ultraviolet, X-rays
- Group 2: Radio Waves, Infrared, Visible Light