(a) Arrange the following radiations in the order of their increasing wavelength:
X-rays, infrared rays, radio waves, gamma rays, and micro waves.
(b) Name the radiation which is used for satellite communication

Answer

### Step-by-Step Solution:

**(a) Arrange the following radiations in the order of their increasing wavelength:**

1. **Understand the Electromagnetic Spectrum**: The electromagnetic spectrum is a range of all the different frequencies of electromagnetic radiation. The order of electromagnetic waves from shortest to longest wavelength is as follows: gamma rays, X-rays, ultraviolet rays, visible light, infrared rays, microwaves, and radio waves.

2. **Identify the Given Radiations**: The radiations we need to arrange are:
- Gamma rays
- X-rays
- Infrared rays
- Microwaves
- Radio waves

3. **Determine the Wavelengths**:
- Gamma rays have the shortest wavelength (around \(10^{-11}\) to \(10^{-9}\) meters).
- X-rays have a slightly longer wavelength (around \(10^{-9}\) to \(10^{-7}\) meters).
- Infrared rays have longer wavelengths than X-rays (around \(10^{-7}\) to \(10^{-4}\) meters).
- Microwaves have even longer wavelengths (around \(10^{-4}\) to \(10^{-1}\) meters).
- Radio waves have the longest wavelengths (greater than \(10^{-1}\) meters).

4. **Arrange in Increasing Wavelength**: Based on the above information, we can arrange the radiations in order of increasing wavelength:
- Gamma rays < X-rays < Infrared rays < Microwaves < Radio waves

**Final Order**:
- Gamma rays < X-rays < Infrared rays < Microwaves < Radio waves

---

**(b) Name the radiation which is used for satellite communication:**

1. **Identify the Type of Radiation Used for Satellite Communication**:
- Satellite communication primarily utilizes microwaves due to their ability to penetrate the atmosphere and their suitable wavelength for transmitting signals over long distances.

2. **Conclusion**:
- The radiation used for satellite communication is **Microwaves**.

### Summary of Answers:
(a) The order of increasing wavelength is: Gamma rays < X-rays < Infrared rays < Microwaves < Radio waves.
(b) The radiation used for satellite communication is Microwaves.

---