In this lesson, let us understand the power of radio wave based on the Inverse Square Law of Electro-Magnetic Radiation. Earlier we had learnt about the terms Phase and Phase Difference in the context of radio waves.

### POWER OF RADIO WAVE

The power of Radio Wave refers to the strength or intensity of the electro-magnetic waves used in radio communication. It is measured in units like watts or milliwatts. The power of Radio Waves determines their range, ability to penetrate obstacles, and the quality of the received signal in radio communication systems.

We know that power of any wave be it sound or light wave reduces with increase in distance from the transmitter. Similarly, power of Radio Waves would also reduce with increase in distance from the transmitter.

### INVERSE SQUARE LAW OF EM RADIATION

Inverse square law of electromagnetic radiation defines the power required for effective range of a transmitter. Power available is inversely proportional to the square of the range. Therefore, power transmitted must be increased four times to double the range.

- [LAND RANGE ~ 3 X SQUARE ROOT OF POWER]
- [SEA RANGE ~ 2 X SQUARE ROOT OF POWER]

In this lesson, we have understood about the power required for a certain Radio Wave Transmission for a pre-determined distance. In the next post, we shall understand about the Polar Diagram of EM Wave.