Write two main properties of ultrasound

(i) Write two main properties of ultrasound.
(ii) Mention one application of ultrasound in (a) industries (b) medical field,

(i) The two main properties of ultrasound are
(a) High frequency
(b) These travel along well defined path even in presence of obstacles.
(ii) (a) In industries, ultrasound is used to detect cracks and flaws in metal blocks.
(b) In medical field, ultrasound is used to break stones in gall bladder and kidney.