iGCSE EDEXCEL PHYSICS DISCUSSION 2012

Makes sense, but it was a 3 mark question, and we had already stated the equation for the question above
I just don't understand why you would get 3 marks for 78x10

1 mark for rearranging the right equation
1 mark for the calculation
1 mark for the correct answer

Reply 321

Coco406

Original post by AM.95

1 mark for rearranging the right equation
1 mark for the calculation
1 mark for the correct answer

That's really generous though, apart from the coin question, all of the other calculations were only two marks?

Reply 322

lkj27

did anyone else notice that one of the questions was state the energy transferred equation thing and it had it on the formula sheet?

Reply 323

g_l

:O
I think i got the LDR question wrong
I said resistance increases with light intensity
I referenced to street lamps and how they have a high resistance in daytime and low resistance in night time to allow current to pass through the circuit to turn the light on...
Ooopss........
How many marks is that question? Will I lose too many marks?

Reply 324

ak2109

1

Original post by g_l

:O
I think i got the LDR question wrong
I said resistance increases with light intensity
I referenced to street lamps and how they have a high resistance in daytime and low resistance in night time to allow current to pass through the circuit to turn the light on...
Ooopss........
How many marks is that question? Will I lose too many marks?

3 marks

Reply 325

member963009

OP

Original post by lkj27

did anyone else notice that one of the questions was state the energy transferred equation thing and it had it on the formula sheet?

YES! Haha I loled in the exam room :tongue:

Reply 326

Coco406

I'm now 100% convinced that 780J is right, so just want to apologise to anyone who got 0.009J and I said it was right, and also to everyone who got 780J- think you're correct :smile:

Reply 327

ak2109

1

I'm now extremely nervous over this paper. :/ I'm not sure how I did, think I got the LED being more efficient or something over a filament lamp wrong. I wrote about it losing less energy as heat, or something like that. Is this correct?

Reply 328

AM.95

I put the efficiency of a filament lamp is hugely decreased due to the high current flowing through the filament which causes the filament to heat up leading to energy losses, whereas in an LED less heat is lost and more is emitted as light leading to greater efficiency.

Btw the way i remember the LDR thing is LIGHT DECREASES RESISTANCE

http://physicsnet.co.uk/wp-content/uploads/2010/06/LDR-graph.jpg

That was the graph i used

(edited 11 years ago)

Reply 329

thetejmaster

can anyone put an unoffical ms up?
so far think ive got nearly everything right :P
also, can anyone got the paper from their centre?

Reply 330

SupremeNunchucks

1

Original post by Coco406

I'm now 100% convinced that 780J is right, so just want to apologise to anyone who got 0.009J and I said it was right, and also to everyone who got 780J- think you're correct :smile:

What formula did you use for that question? :s-smilie:

I used power= energy transferred/time.. did i read the question wrong? >.<

Reply 331

member963009

OP

Original post by ak2109

I'm now extremely nervous over this paper. :/ I'm not sure how I did, think I got the LED being more efficient or something over a filament lamp wrong. I wrote about it losing less energy as heat, or something like that. Is this correct?

yes thats right :smile:

!

Reply 332

Coco406

Original post by SupremeNunchucks

What formula did you use for that question? :s-smilie:

I used power= energy transferred/time.. did i read the question wrong? >.<

Yeah I used that equation :smile:

But I forgot the relationship between watts and joules... I thought it meant 78W were generated on a windy DAY- as in 78W in 24hours, which just cannot be true :frown:

Did you get 780J? If so, I think you're correct :smile:

Reply 333

Graceyfave

Original post by g_l

:O
I think i got the LDR question wrong
I said resistance increases with light intensity
I referenced to street lamps and how they have a high resistance in daytime and low resistance in night time to allow current to pass through the circuit to turn the light on...
Ooopss........
How many marks is that question? Will I lose too many marks?

I'm not sure how lenient, but they might give you one for mentioning resistance or error carried forward etc. if your graph was good they might give you one. I mean markschemes can be quite generous so keep hope :smile:

This was posted from The Student Room's iPhone/iPad App

Reply 334

g_l

Original post by Graceyfave

I'm not sure how lenient, but they might give you one for mentioning resistance or error carried forward etc. if your graph was good they might give you one. I mean markschemes can be quite generous so keep hope :smile:

This was posted from The Student Room's iPhone/iPad App

Hey thanks :smile:

DID ANYONE NOTICE THAT THE CAR WAS HEAVIER THAN THE AEROPLANE LOLOLOL

Reply 335

Coco406

I think I got 100 in this paper (roughly) Thing is I found last Summer's paper easier, and the A* was 136/180. Do you think it will be similar this year, or a lot higher?

Reply 336

g_l

Original post by Coco406

I think I got 100 in this paper (roughly) Thing is I found last Summer's paper easier, and the A* was 136/180. Do you think it will be similar this year, or a lot higher?

SAME i think i got a similar mark to yourse
Hmmm Depends because:
physics boundaries are usually lower than other sciences
depends on how well everyone else does...in this exam and next wednesday's exam... (for triples)
The layout is different so people may have gotten different marks?

Reply 337

thextractor007

Original post by Relaxedexams

IR - Skin burns
UV - damage to surface cells and blindness

I chose UV but it might equally have been IR.

There will prolly be only one answer, not 2 :P

EDIT
"Snow blindness or photokeratitis, a type of temporary eye damage caused by snow reflecting UV light" - From Wikipedia