alleryStart learning →Ultrasonic waves are used in industry to
ADetect cracks inside metal castings
BIncrease the size of metal castings
CReduce the price of metal castings
DChange the colour of metal castings
Answer & Solution
Correct answer: A. Detect cracks inside metal castings
1. The chapter lists non-destructive testing as an industrial use.
2. Ultrasonic waves are sent into a casting.
3. Reflections from internal cracks are picked up by detectors.
4. So flaws can be located without breaking the casting.
_Source: Selina Concise Physics Class 9, Ch 8 Sound (Mistral OCR'd PDF), section on ultrasonic applications_
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