Edexcel Physics Unit 2 "Physics at work" June 2013

Competition - post a photo you've taken of nature >>

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hey, does anyone on here know whether we need to learn about the evidence which support the wave/particle theory or whether we only need to know how to explain the evidence?

Do both since Edexcel may give you a big bomb surprise!

Learn observations of the photoelectric effect and be able to say why it supports particle model and not the wave model of light.

Reply 221

Randy123

could someone please explain to me the observation of the photoelectric effect...i understand why it supports the particle model of light and not the wave but if someone could summarise the observation and experiment itself i would be grateful

Reply 222

lob.dub

Anyones got jan 2013 paper unit 2?????

Reply 223

Randy123

Original post by krisshP

Do both since Edexcel may give you a big bomb surprise!

Learn observations of the photoelectric effect and be able to say why it supports particle model and not the wave model of light.

thank you..hopefully they will just ask how the photoelectric effect supports it haha also do you know if we need to know any other observations like the double slit experiment
thankyou

Reply 224

krisshP

Original post by lob.dub

Anyones got jan 2013 paper unit 2?????

http://www.thestudentroom.co.uk/showthread.php?t=2262586

Reply 225

krisshP

Original post by lob.dub

Anyones got jan 2013 paper unit 2?????

http://www.thestudentroom.co.uk/showthread.php?t=2262586

Original post by Randy123

Look at the mark scheme for the January 2013 unit 2 paper now.

Reply 226

Jaydude

Original post by krisshP

http://www.thestudentroom.co.uk/showthread.php?t=2262586

Thats the economics paper, unless I've missed it somewhere in the post?

Reply 227

krisshP

Original post by Jaydude

Thats the economics paper, unless I've missed it somewhere in the post?

Oops sorry
http://www.mediafire.com/?5djntd8dd7ykb

Reply 228

Jaydude

Original post by krisshP

Oops sorry
http://www.mediafire.com/?5djntd8dd7ykb

Thanks

Reply 229

ambbs

Bit confused about Jan 11, 19aii) - attached the question and MS but I don't understand why you divide the wavelength from i) by 4? Thanks phys q.png

Reply 230

JoshThomas

Original post by ambbs

Bit confused about Jan 11, 19aii) - attached the question and MS but I don't understand why you divide the wavelength from i) by 4? Thanks phys q.png

Divide the wavelength by 2, to find the minimum length for it to be out of phase, and then since that length is the distance there and back, you have to divide by 2 again to find the distance between the two points

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Reply 231

CoolRunner

Original post by JoshThomas

Could you explain this question? I get part A (i) but not part (ii)

Reply 232

ambbs

Original post by JoshThomas

Ah I see, thank you! I didn't grasp the idea that the length was the distance there AND back which is where I got stuck :smile:

cheers! Run out of rep but would pos rep you if I could :biggrin:

Reply 233

JoshThomas

Original post by CoolRunner

Could you explain this question? I get part A (i) but not part (ii)

Which questionnn? :smile:

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Reply 234

Boy_wonder_95

Original post by StUdEnTIGCSE

Well you can show it by calculus

Spoiler

that was quite neat, how do you know this stuff? :tongue:

Reply 235

justinawe

Original post by Boy_wonder_95

that was quite neat, how do you know this stuff? :tongue:

It's on wikipedia :colonhash:

Reply 236

RoyalBlue7

Original post by Boy_wonder_95

that was quite neat, how do you know this stuff? :tongue:

Original post by justinawe

It's on wikipedia :colonhash:

Me no plagiarise from Wikipedia :tongue:

My twin bro was reading the textbook and all of a sudden challenged me to prove it. So I proved it. I just had to take out the textbook and transfer it in.

Its not a valid proof anyway. :ahee:

Edit: I can upload a pic of my original I from the textbook itself if you are bothered :biggrin:

that's the spirit..

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(edited 10 years ago)

Reply 237

justinawe

Original post by StUdEnTIGCSE

Me no plagiarise from Wikipedia :tongue:

My twin bro was reading the textbook and all of a sudden challenged me to prove it. So I proved it. I just had to take out the textbook and transfer it in.

Its not a valid proof anyway. :ahee:

Edit: I can upload a pic of my original I from the textbook itself if you are bothered :biggrin:

that's the spirit..

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Yeah, looking at Wikipedia, the calculus-based proof there is different, so can't be plagiarised :tongue:

Reply 238

Branny101

Just to clarify, does refraction only happen from a less dense to more dense medium?
And TIR only occurs in the more dense medium?

Thanks :s-smilie:

EDIT: What is it you put on the top and bottom of the Snell's law equation, like when do you know what, 'velocity', for example to put on the numerator or denominator ?

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(edited 10 years ago)

Reply 239

krisshP

Original post by Branny101

Just to clarify, does refraction only happen from a less dense to more dense medium?
And TIR only occurs in the more dense medium?

Thanks :s-smilie:

EDIT: What is it you put on the top and bottom of the Snell's law equation, like when do you know what, 'velocity', for example to put on the numerator or denominator ?

Posted from TSR Mobile

Yes, TIR occurs in the denser medium.

Not sure what you mean by refraction. Refraction can occur when going from a more dense to less dense medium OR from less dense medium to more dense medium.

U=velocity1/velocity2

Or

U=sin I/sin r

Both equations should give the same refractive index.

If they give you velocities, use U=velocity 1/velocity 2. If they give angles of incidence and refraction, use U=sin I/sinr