The frequency from 3Hz to 30MHz is known as

Options

A. Audio band
B. Medium frequency band
C. Very high frequency band
D. High frequency band

Answer

To determine what the frequency range from 3 Hz to 30 MHz is known as, we will analyze the given frequency bands and see where this range fits.

### Step-by-Step Solution:

1. **Identify the Frequency Range**:
- The given frequency range is from 3 Hz to 30 MHz.
- In scientific notation, this can be expressed as:
- 3 Hz = \(3 \times 10^0\) Hz
- 30 MHz = \(30 \times 10^6\) Hz = \(3 \times 10^7\) Hz

2. **Analyze the Frequency Bands**:
- **Audio Band**: The frequency range for the audio band is from 20 Hz to 20 kHz (or \(20 \times 10^3\) Hz).
- **Medium Frequency Band**: The medium frequency band ranges from 300 kHz (or \(3 \times 10^5\) Hz) to 3 MHz (or \(3 \times 10^6\) Hz).
- **High Frequency Band**: The high frequency band ranges from 3 MHz (or \(3 \times 10^6\) Hz) to 30 MHz (or \(3 \times 10^7\) Hz).
- **Very High Frequency Band**: The very high frequency band ranges from 30 MHz (or \(3 \times 10^7\) Hz) to 300 MHz (or \(3 \times 10^8\) Hz).

3. **Determine the Overlap**:
- The frequency range from 3 Hz to 30 MHz includes:
- The audio band (from 20 Hz to 20 kHz)
- The medium frequency band (from 300 kHz to 3 MHz)
- The high frequency band (from 3 MHz to 30 MHz)
- Therefore, the range from 3 Hz to 30 MHz encompasses all three bands: audio, medium frequency, and high frequency.

4. **Conclusion**:
- The frequency range from 3 Hz to 30 MHz is known as a combination of the audio band, medium frequency band, and high frequency band.

### Final Answer:
The frequency range from 3 Hz to 30 MHz is known as the audio band, medium frequency band, and high frequency band.

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