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A stone thrown into still water, creates...

A stone thrown into still water, creates a circular wave pattern moving radially outwards. If r is the distance measured from the centre of the pattern, the amplitude of the wave varies as

A

`r ^(-(1)/(2))`

B

`r ^(-1)`

C

`r ^(-2)`

D

`r ^(- (3)/(2))`

Text Solution

Verified by Experts

The correct Answer is:
A
For circular waves (propagating in `2-D` space i.e. on the surface) we have `I prop (1)/(r )`
But `I prop A ^(2) implies A ^(2) prop I implies A prop sqrtI`
`therefore A prop (I)/(sqrtr) implies A prop r ^(-1//2)`
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KUMAR PRAKASHAN-WAVES-SECTION-E (Multiple Choice Questions (MCQs)) (MCQs asked in Gujarat Board and Competitive Exams)
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