Communication through free space using radio waves takes place over frequency range of

Options

A. Few tens of MHz to a few GHz
B. Few tens of KHz to a few hundreds of KHz
C. Few tens of GHz to a few hundreds of GHz
D. Few hundreds of GHz to few thousands of GHz

Answer

To determine the frequency range for communication through free space using radio waves, we can follow these steps:

### Step 1: Understand the Frequency Range of Radio Waves
Radio waves are part of the electromagnetic spectrum and have a specific frequency range. The frequency range for radio waves is generally accepted to be from 3 kHz (3 x 10^3 Hz) to 300 GHz (3 x 10^11 Hz).

### Step 2: Identify the Relevant Subrange for Communication
For communication purposes, particularly in free space, we often focus on the frequency range that is most commonly used. This range typically falls between 1 MHz (1 x 10^6 Hz) and 1 GHz (1 x 10^9 Hz).

### Step 3: Convert Frequency Units
- 1 MHz = 10^6 Hz
- 1 GHz = 10^9 Hz

### Step 4: State the Frequency Range
Thus, the frequency range for communication through free space using radio waves is from 1 MHz to 1 GHz, which can also be expressed as:
- From 10^6 Hz (megahertz) to 10^9 Hz (gigahertz).

### Step 5: Conclusion
The communication through free space using radio waves typically occurs over a frequency range of **1 MHz to 1 GHz**.

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