Which waves are used in echocardiography?
Fill in the blanks.
(1) Sound waves need …………….. medium for propagation.
(2) Technique of echocardiography is based on reflecting property of …………….. waves.
(3) Sound produced by vibration of simple pendulum is …………….. sound.
(4) For determination of the depth of the sea …………….. technique is used.
(5) Pitch of a sound depends upon ………………. of wave.
(a) Define the following terms : (a) Echolocation (b) Echocardiography, and (c) Ultrasonography.
(b) Name an animal which navigates and finds food by echolocation.
(c) Which of the two produces ultrasonic waves: porpoise or whale?