Topic: Engineering Physics
The frequency of ultrasonic waves is
- A. less than 20 Hz
- B. between 20 to 10000 Hz
- C. between 20 to 20000 Hz
- D. above 20000 Hz
Answer: D. above 20000 Hz
Explanation: Range of frequency of waves: Infrasonic <= 20 Hz, Sonic 20 Hz to 20 kHz, Ultrasonic > 20 kHz.