Question

Which of the following statement(s) is/are correct?

• A. Ultrasonic sound has a frequency greater than 20 kHz.
• B. Ultrasonic sound has a frequency lesser than 20 kHz.
• C. Ultrasonic sound carries high energy compared to infrasound of same amplitude.
• D. Ultrasonic sound does not bend appreciably at edges of an obstacle because of its small wavelength.

Answer 1

Answer: (A), (C), (D)

The correct options are
A

Ultrasonic sound has a frequency greater than 20 kHz.

C

Ultrasonic sound carries high energy compared to infrasound of same amplitude.

D

Ultrasonic sound does not bend appreciably at edges of an obstacle because of its small wavelength.

Ultrasonic sounds are those having a frequency greater than 20 kHz.

Properties of ultrasound:

(a) Due to high frequency, ultrasonic sound carries high energy compared to audible or infrasonic sounds of the same amplitude.

(b) Ultrasonic sound does not bend appreciably at edges of an obstacle (high directivity) because of its small wavelength.