Space wave propagation is used in
(`a`) microwave communication
(`b`) satellite communication
(`c`) TV transmission

Options

A. television communication
B. radar communication
C. microwave communication
D. All of them

Answer

To determine which of the options (microwave communication, satellite communication, or TV transmission) uses space wave propagation, we need to understand what space wave propagation is and its characteristics.

### Step-by-Step Solution:

1. **Understanding Space Wave Propagation**:
- Space wave propagation refers to the transmission of radio waves that occurs within the troposphere, typically within 20 kilometers of the Earth's surface.
- It is characterized by the use of high-frequency waves that can travel long distances and can be reflected by the ionosphere.

2. **Analyzing Microwave Communication**:
- Microwave communication uses a beam of radio waves in the microwave frequency range.
- Since microwaves are high-frequency waves, they are suitable for space wave propagation.
- Therefore, space wave propagation is indeed used in microwave communication.

3. **Analyzing Satellite Communication**:
- Satellite communication involves transmitting signals between satellites and various points on Earth.
- This type of communication typically covers large distances, and high-frequency waves are used.
- Hence, space wave propagation is also applicable in satellite communication.

4. **Analyzing TV Transmission**:
- TV transmission involves the use of high-frequency waves to transmit audio and video signals.
- In many cases, satellite links are used for TV transmission, which also implies the use of space wave propagation.
- Therefore, space wave propagation is utilized in TV transmission as well.

5. **Conclusion**:
- After analyzing all three options, we can conclude that space wave propagation is used in all of them: microwave communication, satellite communication, and TV transmission.

### Final Answer:
Space wave propagation is used in:
- (a) Microwave communication
- (b) Satellite communication
- (c) TV transmission