Edexcel Unit 2: Physics at Work ~9th June 2014

Original post by bobo19966

But don't know how to answer when rotate 360 I just simply write will see only one image!!! Btw that image maybe just taken after finish writing the paper :P

I compared the two materials, as the one in the photo was not the polaroid (I don't think). Basically said that the material shown is allowing multiple planes of light to pass through and portray 2 images, whereas when you use a polarising filter you only see the one image due to plane polarisation. (this is the bit I'm not sure on either) Rotating the filter will produce dark and light versions of the image every 90 deg as you are not allowing light that isn't in the particular plane to pass through. eek

Reply 921

Arazamataz

Original post by jtbteddy

LOOOL really???? What was the question like? I did ual, my polarisation question was about a laser light

Posted from TSR Mobile

Yep haha, it was about filters, showing two of the same image of the paper reference box for 6PH02.

Reply 922

Edac

2

I got that bit and facepalmed

Edexcel physics is so unprofessional

Reply 923

cerlohee

16

Original post by Arazamataz

I compared the two materials, as the one in the photo was not the polaroid (I don't think). Basically said that the material shown is allowing multiple planes of light to pass through and portray 2 images, whereas when you use a polarising filter you only see the one image due to plane polarisation. (this is the bit I'm not sure on either) Rotating the filter will produce dark and light versions of the image every 90 deg as you are not allowing light that isn't in the particular plane to pass through. eek

I wrote this too :smile:

Reply 924

bobo19966

2

Original post by Arazamataz

I compared the two materials, as the one in the photo was not the polaroid (I don't think). Basically said that the material shown is allowing multiple planes of light to pass through and portray 2 images, whereas when you use a polarising filter you only see the one image due to plane polarisation. (this is the bit I'm not sure on either) Rotating the filter will produce dark and light versions of the image every 90 deg as you are not allowing light that isn't in the particular plane to pass through. eek

Omg lost at least 3 marks out of 4 :frown:

Reply 925

MO2898

7

Original post by cerlohee

I wrote this too :smile:

Huh?! I thought the material on the front of the paper was that iceland crystal or whatever you call it :frown:

!

But if I did name it wrongly, any lost marks?

Reply 926

AdilMalikN

1

Original post by bill223

Time to return - Calculate distance using t=s/v

Frequency - Doppler effect higher frequency return when rain is moving towards detector

Intensity - Higher amount of rain means more of pulse returned therefore greater intensity of return

For intensity, i remember as a fact that water absorbs microwaves,so more water means less intensity reflection?

Reply 927

iceangel8

14

Original post by MO2898

Huh?! I thought the material on the front of the paper was that iceland crystal or whatever you call it :frown:

!

But if I did name it wrongly, any lost marks?

the exam paper would be pretty heavy if that was the case, and valuable

Reply 928

jamez870

11

Original post by André3000

Why would that be the case, you need to leave time for the pulse to be emitted and then returned so it would be the longer distance?

That's what I thought, seems logical

Reply 929

bob wayne

does anyone remember or know how to show the cross sectional area of the thermostat to be 2x10^-7m^2. I had no idea how to do it. I found that 6 mark question confusing and does anyone remember what they got for the phase difference and how they went about answering that 4 mark question. I thought this was a decent paper though. Probably lost about 30 marks maximum.

Reply 930

Destrian

2

Original post by bob wayne

does anyone remember or know how to show the cross sectional area of the thermostat to be 2x10^-7m^2. I had no idea how to do it. I found that 6 mark question confusing and does anyone remember what they got for the phase difference and how they went about answering that 4 mark question. I thought this was a decent paper though. Probably lost about 30 marks maximum.

The first 8 wires could be measured as 4 cm, so there was 0.5 cm as the diameter of each wire; radius = 0.00025m

Cross sectional area of a wire = πr^2, giving you about 1.94x10^-7

(edited 9 years ago)

Reply 931

Edac

2

Original post by bob wayne

does anyone remember or know how to show the cross sectional area of the thermostat to be 2x10^-7m^2. I had no idea how to do it. I found that 6 mark question confusing and does anyone remember what they got for the phase difference and how they went about answering that 4 mark question. I thought this was a decent paper though. Probably lost about 30 marks maximum.

It was a Rheostat btw
I calculated it by working out how many coils there were in 3cm (55 coils) then I knew the diameter of each wire was 0.03/55 and using the equation (d/2)^2*pi = cross sectional area

I got the phase difference as 0 (since they were in phase at this point), but I think any multiple of 2pi or 360 degrees is fine

Reply 932

bob wayne

jesus christ that means 3 marks definitely gone. I wasn't going to get that right anyway :/

Reply 933

AdilMalikN

1

what was up with that last question? i just said wavelength was in meters so uncertainty is low? that was wierd.

Reply 934

rdknighton

I just realised that water absorbs microwaves after the exam. Surely this means that the microwaves wouldn't be reflected so there would be no way to work out how far they the rain was away or measure the speed?

Also, what mark do you think an A will be? I would say around 60/61

Reply 935

MO2898

7

Original post by iceangel8

the exam paper would be pretty heavy if that was the case, and valuable

I meant the transparent block that was placed on the 6PH02

Reply 936

iceangel8

14

Original post by MO2898

I meant the transparent block that was placed on the 6PH02

haha oh sorry :smile:

Reply 937

pyaesone

2

will the unofficial mark scheme be out for this paper?

Reply 938

Edac

2

Original post by rdknighton

I just realised that water absorbs microwaves after the exam. Surely this means that the microwaves wouldn't be reflected so there would be no way to work out how far they the rain was away or measure the speed?

Also, what mark do you think an A will be? I would say around 60/61

Yeah microwaves are absorbed by water, hence why microwave ovens work.
It was a pretty silly question, but I guess some of the waves are reflected otherwise the question wouldn't make sense; there would be no way of calculating any of the things it asked you unless some waves were reflected