# Radius of circular impulse wave in the hemisphere bowl

## Homework Statement

hi all, why the wave is reflected back form the centre when it is at the distance of 200mm? why the wave cant go beyond 200mm to reach 250mm from the side of bowl?

## The Attempt at a Solution

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## Answers and Replies

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TSny
Homework Helper
Gold Member
Can you describe the shape of the wavefront just after tapping the side of the bowl? I'm not sure, but you might have a misconception about this. If in doubt, try it in the kitchen

What does the wavefront in the problem look like at t = 0.8 s?

Can you describe the shape of the wavefront just after tapping the side of the bowl? I'm not sure, but you might have a misconception about this. If in doubt, try it in the kitchen

What does the wavefront in the problem look like at t = 0.8 s?
the wavefront move until the another end from one end and reflect back.

Nathanael
Homework Helper
the wavefront move until the another end from one end and reflect back.
So you're saying it would be like a line moving across the bowl and then back?

Yes. Is it wrong?

NascentOxygen
Staff Emeritus
Science Advisor
hi all, why the wave is reflected back form the centre when it is at the distance of 200mm? why the wave cant go beyond 200mm to reach 250mm from the side of bowl?
It does seem wrong to use the word "reflect" to describe the wave progressing through the centre of the bowl. There is no discontinuity in the medium there for a wave to "reflect" off.

There is no phase inversion, yet they imply it can be viewed as 100% "reflection"?

TSny
Homework Helper
Gold Member
the wavefront move until the another end from one end and reflect back.
Did you do the experiment?

Here is what I observed. Picture A shows the water sitting still in the bowl before tapping the bowl.

B, C, and D show times just after tapping the bowl on the left with the handle of a knife.

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Did you do the experiment?

Here is what I observed. Picture A shows the water sitting still in the bowl before tapping the bowl.

B, C, and D show times just after tapping the bowl on the left with the handle of a knife.
sorry i cant understand your photo here. can i still say that the water the wavefront move until the another end from one end and reflect back. which means the water wave can move until 400mm from one end and then only reflect back? which is also (assuming the water wave is produced at the left ) means the water wave is at 150 mm form the right...

Nathanael
Homework Helper
So you're saying it would be like a line moving across the bowl and then back?
Yes. Is it wrong?
As you can see from TSny's pictures, that is not what happens. (It is not a line; what shape is it?)

Circular waves spread out?

NascentOxygen
Staff Emeritus
Science Advisor
Circular waves spread out?
Perhaps you could write a few sentences in response to those trying to help you? By confining yourself to a single staccato phrase, you have misled some into thinking you can't conceive of circular wave propagation. Well. I think you have managed it, anyway ...

Maybe I'm the one who's got it wrong. You have tried tapping on the side of a bowl of water?

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