AQA Physics PHYA4 - Thursday 11th June 2015 [Exam Discussion Thread]

Scroll to see replies

Reply 4860

000alex

If you got 4.8 for emf induced I think you accidently multiplied by 40 coils twice

Reply 4861

Kennethm

Original post by DysonCube

No, the one in section B with the graph where it asks you to work out the field strength at 0.4m. I got 1875Vm-1 but the MS on here says 1560Vm-1.

i got 1875 aswell. I still think I'm right lol

basically - you find the corresponding value for 2.5 on the graph since 1/0.4 is 2.5.

which is -750V then you use the potential gradient equation which is valid because the same rules from grav field apply to electric fields.

E = V/r

so its 750 x 2.5 = 1875. Makes sence! Not sure where 1560 came from lol.

Yh
It was 1875

Original post by Kennethm

Original post by Boton

Yh
It was 1875

I think you both accidentally used 750V in your calculations. The corresponding potential at r=0.4m (hence at 1/r = 2.5) was 625V.

As such, you do E=v/r

So E = 625/0.4

= 1562.5 Vm^-1

Posted from TSR Mobile

Reply 4864

MSB47

Plus if you use the standard field strength equation you get 1560 too

Reply 4865

Kennethm

Original post by CD223

ohhh rip

pretty sure thats like 1 mark lost tho - correct equation used blah blah

Reply 4866

CD223

Original post by Kennethm

ohhh rip

pretty sure thats like 1 mark lost tho - correct equation used blah blah

Not sure how the written will go to be honest. Praying for low boundaries as I made stupid mistakes in section B.

Posted from TSR Mobile

Reply 4867

otterfailure

Original post by xela238

What question are you referencing?

Posted from TSR Mobile

the last one with the 6 marker

Reply 4868

Sbarron

Anyone got a copy of the MC paper?

Reply 4869

QueNNch

HAVE YOU GUYS SEEN THIS
http://www.bbc.co.uk/news/education-33094306

AQA apologises for the question mistake in the exam 😮

Reply 4870

CD223

Original post by Sbarron

Anyone got a copy of the MC paper?

Hopefully one will be uploaded later today.

Posted from TSR Mobile

Reply 4871

dmp1188

What do u guys think the boundaries will be for an a*? Also has anyone done the empa this yr... How did u guys find it?

Reply 4872

_Caz_

Original post by QueNNch

HAVE YOU GUYS SEEN THIS
http://www.bbc.co.uk/news/education-33094306

AQA apologises for the question mistake in the exam 😮

Aqa better disregard the question because imagine how hard we'd get penalised if we didn't include a 'kilo' in our answer. When I did the paper I thought that one resistor being 2000 times more resistive than the other was a bit strange. Fair is fair so the 3 marks should just be taken from the paper.

Posted from TSR Mobile

Reply 4873

Jed-Singh

if we got that question right, where AQA make a mistake, would that be worse for us because then it nullifies our correct answer?

Reply 4874

Kennethm

worked out - 55/75

SO disappointed :frown:

hope these boundaries land me an A.

Reply 4875

CD223

Original post by Kennethm

worked out - 55/75

SO disappointed :frown:

hope these boundaries land me an A.

That's likely to be a mid-A I think. Did you need an A* then? It's so hard to assume you've lost marks on the written though, so I don't know how you've managed to guess that? :s-smilie:

Posted from TSR Mobile

Reply 4876

Kennethm

Original post by CD223

That's likely to be a mid-A I think. Did you need an A* then? It's so hard to assume you've lost marks on the written though, so I don't know how you've managed to guess that? :s-smilie:

Posted from TSR Mobile

i marked it harshly for myself but i feel like its the most accurate mark.

Reply 4877

CD223

Original post by Kennethm

i marked it harshly for myself but i feel like its the most accurate mark.

The only part you can really mark properly is the MC! I'm sure you've done well.

Posted from TSR Mobile

Reply 4878

TheRAG

Can anyone post the graph we were supposed to draw please?

Reply 4879

jordan_bennett14

Thank you! That was actually clear! So a top pan balance can actually read negative? I thought it was just like a normal scale in that it can't read below zero but obviously I realise now that it can :P