The speed of highly penetrating ultrasonic waves is :
(a) lower than those of audible sound waves
(b) higher than those of audible sound waves
(c) much higher than those of audible sound waves
(d) same as those of audible sound waves
In SONAR we use :
(a) ultrasonic waves
(b) infrasonic waves
(c) radio waves
(d) audible sound waves