Sounds of frequency less than 20 Hz are said to belong to the _________ range.

Options

A. Sonic
B. Infrasonic
C. Ultrasonic
D. High-range

Answer

To solve the question regarding the classification of sound frequencies, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Sound Frequency Ranges**:
- Sound is classified based on its frequency, which is measured in Hertz (Hz).
- The human ear can typically hear sounds in the frequency range of 20 Hz to 20,000 Hz.

2. **Identifying the Categories**:
- Sounds with frequencies below 20 Hz are categorized as infrasonic sounds.
- Sounds with frequencies above 20,000 Hz are categorized as ultrasonic sounds.

3. **Determining the Correct Range**:
- Since the question specifies sounds of frequency less than 20 Hz, we need to identify the correct term for this range.
- Based on the classification, sounds with frequencies less than 20 Hz belong to the infrasonic range.

4. **Final Answer**:
- Therefore, the sounds of frequency less than 20 Hz are said to belong to the **infrasonic range**.