Waves questions from Cambridge physics paper 9702

[Michael Marchenko]

I want to ask about question 27 in Cambridge university physics paper 9702/01 of October/November 2008

https://physics18.weebly.com/uploads/5/9/8/5/59854633/9702_w08_qp_01.pdfand question 30 in Cambridge university physics paper 9702/12 of May/June 2012.

https://physics18.weebly.com/uploads/5/9/8/5/59854633/9702_s12_qp_12.pdfIs the motion of the transmitter or receiver important?

Are they both about standing waves and that is why the distance between the neighboring maxima = half of the wavelength?

Are these questions the same?

 

[berkeman]

Thread closed temporarily for Moderation...

 

[berkeman]

I want to ask about question 27 in Cambridge university physics paper 9702/01 of October/November 2008

https://physics18.weebly.com/uploads/5/9/8/5/59854633/9702_w08_qp_01.pdfand question 30 in Cambridge university physics paper 9702/12 of May/June 2012.

https://physics18.weebly.com/uploads/5/9/8/5/59854633/9702_s12_qp_12.pdfIs the motion of the transmitter or receiver important?

Are they both about standing waves and that is why the distance between the neighboring maxima = half of the wavelength?

Are these questions the same?

Welcome to the PF, @Michael Marchenko

Your first post is in a format that is unusual for our schoolwork forums. Usually students post a single problem using the Homework Help Template that you are provided when starting a new schoolwork thread, and fill out their work in the Template to show where they are in solving the problem.

But your question is a bit different. You are asking a general question about the commonality between two study questions. It's still appropriate to post this here in the schoolwork forums, but there are a couple of things you could do that would help us to help you on this question.

** First, please take screenshots of the two problems, and Upload them to your next Reply. It's a bit unreasonable to ask helpers to look through two long PDF files to try to find the problems you are asking about.

** Second, please share your thoughts about the question you are asking -- Do you think the questions are asking about the same thing?

Thanks very much. Thread is re-opened, and we are looking forward to your reply.

 

[Michael Marchenko]

Welcome to the PF, @Michael Marchenko

Your first post is in a format that is unusual for our schoolwork forums. Usually students post a single problem using the Homework Help Template that you are provided when starting a new schoolwork thread, and fill out their work in the Template to show where they are in solving the problem.

But your question is a bit different. You are asking a general question about the commonality between two study questions. It's still appropriate to post this here in the schoolwork forums, but there are a couple of things you could do that would help us to help you on this question.

** First, please take screenshots of the two problems, and Upload them to your next Reply. It's a bit unreasonable to ask helpers to look through two long PDF files to try to find the problems you are asking about.

** Second, please share your thoughts about the question you are asking -- Do you think the questions are asking about the same thing?

Thanks very much. Thread is re-opened, and we are looking forward to your reply.

I cannot copy the questions separately. Sorry. I am trying. May be I will do that later.

 

[berkeman]

I cannot copy the questions separately. Sorry. I am trying. May be I will do that later.

I can try to do it for you, but all you have to do is take Windows screenshots of the individual pages, and paste them into JPEG images in Paint or a similar program. Are you familiar with using Alt-PrntScrn to take screenshots in Windows?

 

[Michael Marchenko]

 

[Michael Marchenko]

 

[Michael Marchenko]

How do I take into account the motion of the source or the receiver?

 

[berkeman]

How do I take into account the motion of the source or the receiver?

It looks like it is just a matter of constructive and destructive interference as a function of position along the axis in each question. There is no Doppler component in the motion part of the questions, IMO. Is htat your question?

 

[Michael Marchenko]

It looks like it is just a matter of constructive and destructive interference as a function of position along the axis in each question. There is no Doppler component in the motion part of the questions, IMO. Is htat your question?

Doppler effect may be important here. I still do not understand what are the correct answers to these questions and why.

 

[berkeman]

Doppler effect may be important here.

Why do you say that? To include the Doppler effect, we would need to know the velocity of the receiver,.

I still do not understand what are the correct answers to these questions and why.

Can you post the Relevant Equations for simple constructive/destructive wave interference problems like these?

 

[Michael Marchenko]

Why do you say that. To include the Doppler effect, we would need to know the velocity of the receiver, n

Can you post the Relevant Equations for simple constructive/destructive wave interference problems like these?

Doppler effect may be important here because it may have qualitative effect because the relative speed is unknown.

I do not know how to post equations here.

 

[berkeman]

Doppler effect may be important here because it may have qualitative effect because the relative speed is unknown.

Nah, you can safely stop thinking about the Doppler effect in these two problems.

I do not know how to post equations here.

Three options:

1) Type them

2) click on the ∑ above the edit window to get access to some math symbols

3) read the LaTeX tutorial when you click on INFO at the top of the page, and follow it to Help/How-To

 

[Michael Marchenko]

Can you post the Relevant Equations for simple constructive/destructive wave interference problems like these?

For the constructive interference the phase difference must be multiple of 360 degrees.
For destructive interference the phase difference must be odd number of 180 degrees.

 

[berkeman]

For the constructive interference the phase difference must be multiple of 360 degrees.
For destructive interference the phase difference must be odd number of 180 degrees.

That's pretty close. So can you apply those rules to the 2 problems to solve them?

 

[Michael Marchenko]

That's pretty close. So can you apply those rules to the 2 problems to solve them?

Can there be a beat in question 30?
https://en.wikipedia.org/wiki/Beat_(acoustics)