Which one of the following is correct ?

Options

A. A single geostationary satellite can cover the whole part of the earth for microwave communication
B. Atleast three gerostationary salellite in the same orbit around earth.s can cover the whole part of the earth for microwave communication
C. The first Indian communication satellite is Apple
D. The satellite communication is not like the line of sight microwave communication

Answer

To determine which statement is correct regarding geostationary satellites and their coverage for microwave communication, we will analyze each statement step by step.

### Step-by-Step Solution:

1. **Understanding Geostationary Satellites**:
- A geostationary satellite orbits the Earth at a height of approximately 35,800 km above the equator. It moves in sync with the Earth's rotation, making it appear stationary from a fixed point on the Earth's surface.

**Hint**: Remember that geostationary satellites are positioned directly above the equator and match the Earth's rotation period.

2. **Analyzing the First Statement**:
- The first statement claims that a single geostationary satellite can cover the whole part of the Earth for microwave communication.
- In reality, a single geostationary satellite can only cover about one-third of the Earth's surface due to the curvature of the Earth.

**Hint**: Visualize the coverage area of a satellite and consider the Earth's curvature when determining coverage.

3. **Conclusion on the First Statement**:
- Since a single geostationary satellite cannot cover the entire Earth, this statement is **incorrect**.

4. **Analyzing the Second Statement**:
- The second statement suggests that at least three geostationary satellites in the same orbit can cover the whole part of the Earth for microwave communication.
- This is true because three satellites can be positioned at equal intervals (120 degrees apart) in the same orbit, allowing for complete coverage of the Earth's surface.

**Hint**: Think about how multiple satellites can work together to cover areas that a single satellite cannot.

5. **Conclusion on the Second Statement**:
- Since three geostationary satellites can indeed cover the entire Earth, this statement is **correct**.

6. **Analyzing the Third Statement**:
- The third statement claims that the first Indian communication satellite is Apple. This is incorrect; the first Indian communication satellite is INSAT.

**Hint**: Verify historical facts about satellite launches to confirm the accuracy of such statements.

7. **Analyzing the Fourth Statement**:
- The fourth statement discusses line-of-sight microwave communication. Satellite communication generally requires a line-of-sight path, which is essential for effective signal transmission.

**Hint**: Consider the principles of communication technology and the importance of line-of-sight in satellite communications.

### Final Answer:
- The correct statement is: **At least three geostationary satellites in the same orbit around the Earth can cover the whole part of the Earth for microwave communication.**