You are Here: Home >< Physics

# Path Difference and Interference - Quincke's Tube

Announcements Posted on
Four hours left to win £100 of Amazon vouchers!! Don't miss out! Take our short survey to enter 24-10-2016
1. Hi there.

I'm struggling with the question above - I calculated the wavelength of the light which is

340/800 = 0.425m

I'm not too sure where to go from there

Any help will be appreciated - Thanks
2. Bump - Any ideas?
3. (Original post by CrazyFool229)
Bump - Any ideas?
well have you thought about the condition for destructive interference?

also note that for every 1mm you alter D2, the path length in the RHS pipe goes up by 2mm.

PS you mean sound, not light don't you?
4. (Original post by Joinedup)
well have you thought about the condition for destructive interference?

also note that for every 1mm you alter D2, the path length in the RHS pipe goes up by 2mm.

PS you mean sound, not light don't you?
Yeah, sorry I did mean sound.

I did think that for destructive interference to occur it must be 1/2 wavelength path difference minimum which will be 0.2125m of the wavelength - Idk where to from there.
5. Also this might sound stupid - But how did you get the ratio for D1 and D2?
6. Can anyone help?
7. (Original post by CrazyFool229)
Also this might sound stupid - But how did you get the ratio for D1 and D2?
well the vertical length of both pipes is the same and fixed - but the RHS pipe can be lengthened in the horizontal direction - the sound waves have to left to right by D2 and then right to left by D2 - so horizontally it's a 2 way trip.

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: May 1, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### Who is getting a uni offer this half term?

Find out which unis are hot off the mark here

### How to get a 1st class degree

Poll
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.