Question

Identify the wave that is ultrasonic.

A) 400 mHz.
B) 4 MHz.
C) 28 Hz.
D) 2 Hz.

Answer 1

Option B) 4 MHz (megahertz) is the ultrasonic wave among the given options because its frequency is above the human audible range, which is higher than 20 kHz.

Step-by-step explanation:

The student has asked to identify the ultrasonic wave among the given options. Ultrasonic waves are sound waves with frequencies above the upper limit of human hearing, which is typically around 20 kHz (kilohertz). Option B) 4 MHz (megahertz) is an ultrasonic wave because 4 MHz is equivalent to 4000 kHz, which is well above the 20 kHz threshold for human hearing. Options A) 400 mHz (millihertz), C) 28 Hz, and D) 2 Hz are not ultrasonic since their frequencies are far below the audible range for humans, let alone the ultrasonic range.