A relay satellite transmits the television programme from one part of the world to another part continuously because its period

Options

A. Period is greater than the period of rotation of the earth
B. Period is less than the period of rotation of earth
C. Period has no relation with the period of the earth about its axis.
D. Period is equal to the period of rotation of the earth about then its

Answer

To solve the question regarding why a relay satellite can continuously transmit television programs from one part of the world to another, we need to understand the relationship between the satellite's period and the Earth's rotation.

### Step-by-Step Solution:

1. **Understanding Satellite Motion**: A relay satellite is positioned in such a way that it can continuously communicate with a specific area on Earth. This is typically achieved by placing the satellite in a geostationary orbit.

2. **Geostationary Orbit**: A geostationary satellite orbits the Earth at a height where its orbital period matches the Earth's rotational period. This means that as the Earth rotates, the satellite remains fixed over the same point on the Earth's surface.

3. **Earth's Rotation Period**: The Earth completes one full rotation about its axis approximately every 24 hours (specifically, about 23.93 hours, but for simplicity, we use 24 hours).

4. **Matching Periods**: For the satellite to remain over the same point on Earth, it must have the same orbital period as the Earth's rotation period. Therefore, the satellite's period must be equal to the period of rotation of the Earth.

5. **Conclusion**: Since the satellite's period is equal to the period of rotation of the Earth, it can continuously transmit signals to a specific area without interruption.

### Final Answer:
The relay satellite transmits the television program from one part of the world to another continuously because its period is equal to the period of rotation of the Earth about its axis.