Turn on thread page Beta
 You are Here: Home >< Physics

# Polarisation Question watch

1. Hi there, I was just stuck on a question.

OCR Physics Electrons Waves and Photons paper.

http://www.ocr.org.uk/Images/319537-...nd-photons.pdf

Markscheme - http://www.ocr.org.uk/Images/320124-...otons-june.pdf

Question 5 d ii

Q: The detector is rotated 90 degrees about the axis through OQ (what is the effect of the intensity heard.)

How do you know that the signal is (vertically) polarised like the markscheme says, there's no indication of that in the question. Also microwaves are EM waves which are transverse. Thus why does the signal fall to zero?

Your help would be very much appreciated!!!
2. The two speakers are producing plane polarised waves.
3. (Original post by Adam_1999)
The two speakers are producing plane polarised waves.

But how do you know that, microwaves are transverse waves which are normally not polarised
4. (Original post by SmurfyZ)
But how do you know that, microwaves are transverse waves which are normally not polarised
The two sources interfere constructively at O; this causes the waves to vibrate in only one plane.

This is a complete guess. Consult google for more info.
5. (Original post by SmurfyZ)
Hi there, I was just stuck on a question.

OCR Physics Electrons Waves and Photons paper.

http://www.ocr.org.uk/Images/319537-...nd-photons.pdf

Markscheme - http://www.ocr.org.uk/Images/320124-...otons-june.pdf

Question 5 d ii

Q: The detector is rotated 90 degrees about the axis through OQ (what is the effect of the intensity heard.)

How do you know that the signal is (vertically) polarised like the markscheme says, there's no indication of that in the question. Also microwaves are EM waves which are transverse. Thus why does the signal fall to zero?

Your help would be very much appreciated!!!
(Original post by SmurfyZ)
But how do you know that, microwaves are transverse waves which are normally not polarised
I can understand the frustration. I agree that the question is not clearly whether the microwaves are plane-polarised from the source.

My guess is when the question mentions a polariser is placed at the detection point, the transverse waves should be polarised vertically at the source.

You may also want to check with your teacher what are all the necessary conditions for transverse waves to have clear interference pattern. If your teacher include the transverse waves must have same direction of polarisation, then whenever you see such question that involves transverse waves, the waves must be polarised.
6. (Original post by Eimmanuel)
I can understand the frustration. I agree that the question is not clearly whether the microwaves are plane-polarised from the source.

My guess is when the question mentions a polariser is placed at the detection point, the transverse waves should be polarised vertically at the source.

You may also want to check with your teacher what are all the necessary conditions for transverse waves to have clear interference pattern. If your teacher include the transverse waves must have same direction of polarisation, then whenever you see such question that involves transverse waves, the waves must be polarised.
Cheers man, i'll definitely check with my teacher.

Reply
Submit reply
Turn on thread page Beta

### Related university courses

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:
Updated: May 21, 2017
The home of Results and Clearing

### 1,609

people online now

### 1,567,000

students helped last year
Today on TSR

### A-level grade boundaries

Hang on, have Edexcel's come out already?

### University open days

1. Bournemouth University
Clearing Open Day Undergraduate
Fri, 17 Aug '18
2. University of Bolton
Undergraduate Open Day Undergraduate
Fri, 17 Aug '18
3. Bishop Grosseteste University
All Courses Undergraduate
Fri, 17 Aug '18
Poll

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

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