The Physics PHYA2 thread! 5th June 2013

Original post by Jimmy20002012

Is there actually anything you don't know for this exam? :smile:

Thanks for asking :smile:

Well, to be honest, I am not too sure. I will definitely ask when I need help. Thanks :smile:

Reply 382

Original post by Jimmy20002012

Is there actually anything you don't know for this exam? :smile:

I am just being toooo lazy now. I am really tired and so I can not be bothered to do anymore revision at all. I have 2 ICT and 1 physics exam left.

Reply 383

Original post by Jimmy20002012

Is there actually anything you don't know for this exam? :smile:

I am just worried about the 6-marker ones. They are usually the nastiest questions and I do not want to drop any marks as I am aiming for full ums score. :smile:

Reply 384

Original post by NedStark

So the central red graph represents the diffraction grating?

If so, what does the large blue curve and dotted red curve represent? Young's double slit? Really confused as to what each one is.

Basically, when the light beam is diffracted, the fringe pattern (interference) is produced on the screen. However, the middle fringe (which is maximum bright) is the brightest fringe. So, as you look at the fringes away from the middle one, their intensity reduces. And this is exactly what the graph shows. The middle curve has the maximum intensity since the middle fringe is the brightest. Does that make sense? :smile:

Reply 385

username1129244

15

Original post by StalkeR47

Basically, when the light beam is diffracted, the fringe pattern (interference) is produced on the screen. However, the middle fringe (which is maximum bright) is the brightest fringe. So, as you look at the fringes away from the middle one, their intensity reduces. And this is exactly what the graph shows. The middle curve has the maximum intensity since the middle fringe is the brightest. Does that make sense? :smile:

That makes sense, it's the what do the other lines represent on the graph? (Page 204 Nelson Thornes book)

Reply 386

Original post by NedStark

So the central red graph represents the diffraction grating?

If so, what does the large blue curve and dotted red curve represent? Young's double slit? Really confused as to what each one is.

You will get dotted line as shown in the graph. This is given by 'without single slit effect' meaning that all the fringe pattern seen will have the same intensity. :smile:

Reply 387

Original post by NedStark

That makes sense, it's the what do the other lines represent on the graph? (Page 204 Nelson Thornes book)

Also, blue is for the blue light. Remember, red light has longer wavelength which changes the fringe pattern that is given by the equation w=lambda d divided by s. Is that ok?

Reply 388

http://www.thestudentroom.co.uk/showthread.php?t=2367035&page=5&p=42905646#post42905646

This is my thread. I help everyone here! :smile:

Reply 389

Original post by NLoR

On the Jan 13 paper, once you've worked out the wavelength, how do you work out the path difference?

Path difference is the difference in distances between 2 coherent waves. You know that 1 wave which is closer to the detector will have to travel less distance towards the detector from the slit than the other wave. This means there is a path difference between these 2 waves. If the frequency of the wavelengths is given, the wavelength is the path difference since it tells you the distance difference between them 2. (This is only true if you are given frequency of both). :smile:

Reply 390

Goods

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Original post by StalkeR47

I am just worried about the 6-marker ones. They are usually the nastiest questions and I do not want to drop any marks as I am aiming for full ums score. :smile:

This is unit 2. 65/70 is full marks so you get get 1/6 on the 6 marker :smile:

Reply 391

Jimmy20002012

4

Original post by Goods

This is unit 2. 65/70 is full marks so you get get 1/6 on the 6 marker :smile:

Actually it 62 for full ums :smile:

Reply 392

Original post by Goods

This is unit 2. 65/70 is full marks so you get get 1/6 on the 6 marker :smile:

Original post by Jimmy20002012

Actually it 62 for full ums :smile:

Thank you both! :smile:

Reply 393

Goods

16

Original post by Jimmy20002012

Actually it 62 for full ums :smile:

but last years paper was too easy gonna be harder this year

Reply 394

Original post by Jimmy20002012

Actually it 62 for full ums :smile:

Hey Jimmy, do you know how much ums is 1 as-level worth? :smile:

Reply 395

Original post by Goods

but last years paper was too easy gonna be harder this year

It could be harder this year. But the grade boundaries will be low. I predict that it will be 49/70 for an A but I want full UMS. :smile:

Reply 396

username1129244

15

Original post by StalkeR47

You will get dotted line as shown in the graph. This is given by 'without single slit effect' meaning that all the fringe pattern seen will have the same intensity. :smile:

What do they mean by the single slit effect? Is that when a laser shines at a single slit causing diffraction?

Or is single slit the extra slit used in Young's double slit interference, just before the light shines through 2 slits?

Reply 397

Jimmy20002012

4

Original post by StalkeR47

Hey Jimmy, do you know how much ums is 1 as-level worth? :smile:

It's worth 120ums, same as unit 2 :smile:

How did you find the unitb1 exam anyway?

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Reply 398