Ultrasonic have__________________?
Afrequency in the audible range
Ball of above
Cfrequency is greater than 20 kHz
Dfrequency lower than 20 Hz
Correct answer
C. frequency is greater than 20 kHz
Explanation
frequency is greater than 20 kHz is the correct answer. Review the question and compare it with the other choices to remember this fact for future exams.