What type of waves are generated by SONAR device fixed to a fishing ship ?
(a) water waves
(b) radio waves
(c) sound waves
(d) infrared waves
In SONAR we use :
(a) ultrasonic waves
(b) infrasonic waves
(c) radio waves
(d) audible sound waves
Which of the following are used to study the growth of foetus inside the mother's womb ?
(a) radio waves (b) X-rays (c) infrared waves (4) sound waves