Supersonic means

Options

A. frequencies less than 20 Hz
B. same as ultrasonic
C. frequencies much more than that of ultrasonics
D. same as infrasonics

Answer

### Step-by-Step Solution:

1. **Understanding Supersonic:**
- Supersonic refers to objects that travel faster than the speed of sound in a given medium (usually air). The speed of sound is approximately 343 meters per second (or 1235 km/h) at room temperature.

2. **Frequency Context:**
- Frequency is the number of oscillations or cycles per second of a wave, measured in Hertz (Hz). The human audible range is typically from 20 Hz to 20 kHz (20,000 Hz).

3. **Analyzing the Options:**
- **Option 1:** Frequency less than 20 Hz.
- This is incorrect because supersonic refers to speed, not frequency. Supersonic objects travel faster than sound, which corresponds to frequencies greater than 20 kHz.

- **Option 2:** Same as ultrasonic.
- This is correct. Ultrasonic waves have frequencies greater than 20 kHz, which is the same range for supersonic objects in terms of sound waves.

- **Option 3:** Frequency much more than ultrasonic.
- This is incorrect because while supersonic and ultrasonic both refer to frequencies above 20 kHz, supersonic does not imply a frequency much higher than ultrasonic.

- **Option 4:** Same as infrasonic.
- This is incorrect. Infrasonic refers to frequencies below 20 Hz, which is not related to supersonic.

4. **Conclusion:**
- The correct definition of supersonic is that it refers to objects that travel faster than the speed of sound, and in terms of frequency, it is similar to ultrasonic, which is above 20 kHz.

### Final Answer:
Supersonic means objects that travel faster than the speed of sound, and their frequency is similar to ultrasonic, which is greater than 20 kHz.

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