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OCR PHYSICS B G494~ 11th June 2015 AM ~ A2 Physics

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I think the A* boundary won't be too high, remember guys this is TSR so people are bound to find it 'easy'
Original post by urz13
It was using dQ/dt. Find Q when V=0.12 and then dt=60s giving an answer of 0.94uA, I believe


Do you remember what the final voltage was? It was like 3 or 6 or something like that?
Original post by Rhetorical Hips
I think the A* boundary won't be too high, remember guys this is TSR so people are bound to find it 'easy'


I can see where a lot of people would slip up. A lot of the questions weren't exceptionally hard but they took me a while.

I think it's unfair that If you haven't done A2 Maths you'd struggle on that.
Original post by Lewis7253
I can see where a lot of people would slip up. A lot of the questions weren't exceptionally hard but they took me a while.

I think it's unfair that If you haven't done A2 Maths you'd struggle on that.


Yeah I can see logs being a problem if you don't do maths. Asides from that, OCR seem to leave out calculus which is good I guess :smile:
I ran out of time :s

I think that was almost as bad as yesterday's chemistry!

And that finding G question was awful!!!!!!
I got 56?! Wtf?!??!?!!?!?!?!!!
It can't have been 56!

Anyone else think it was harder than normal? I have done about 18past papers for that exam and none of them were that bad! :frown:
Original post by Carys_2
Density was of surface rocks - not factoring different densities of the mantle and core etc.


Yeah I did the same :smile:
Original post by Carys_2
Density was of surface rocks - not factoring different densities of the mantle and core etc.


Yeah I put the same
Quick shoutout to my boy raju sandhu who got full ums in that exam!!🙌🙌


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What did people put for the equipotential lines?
why is kinetic energy not conserved in the collision?? i know it's probably something really easy but i thought it can't be lost to sound because it said something about being in space :-(
Reply 130
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urz13
8
Original post by Rhetorical Hips
Do you remember what the final voltage was? It was like 3 or 6 or something like that?


I didn't calculate the final voltage - I just did Q=0.12C (whatever C was), then dQ/dt = 0.94uA :smile: I think 0.94 is about right as later in the question it said it was originally 1uA, or something!
Original post by rapunzelsa
why is kinetic energy not conserved in the collision?? i know it's probably something really easy but i thought it can't be lost to sound because it said something about being in space :-(



****
I put sound
Reply 132
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urz13
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Original post by rapunzelsa
why is kinetic energy not conserved in the collision?? i know it's probably something really easy but i thought it can't be lost to sound because it said something about being in space :-(

I said it was an inelastic collision and energy was lost as other forms such as heat. Not sure if that's correct though!
Reply 133
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urz13
8
Original post by Lissy14
I ran out of time :s

I think that was almost as bad as yesterday's chemistry!

And that finding G question was awful!!!!!!
I got 56?! Wtf?!??!?!!?!?!?!!!
It can't have been 56!

Anyone else think it was harder than normal? I have done about 18past papers for that exam and none of them were that bad! :frown:


I definitely think it was harder than usual! Very few that I've done have been that level or close to it, and I've done all the past papers too.
Guys, about G being too large. Did anyone notice that it said the mean density of the SURFACE of Earth? The Earth's insides are going to be different density to the surface, therefore G is likely to be way out. That mass of 3x10^24 is like, half of what the actual mass of earth is (6x10^24).
Original post by falconinni
Yeah I put the same


Could we say that the methods are more precise?


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Original post by Rhetorical Hips
Density=Mass/Volume therefore Mass=Density x Volume, you were given a rough estimate of density and volume=4/3 x pi x radius cubed

EDIT on the topic of that question, what reason did you guys give for G being to large?


Okay, I get the theory behind it, but the only value for density it gave you was for density of surface rocks on Earth? typo, or am I just misinterpreting what that means?
Reply 137
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STATER
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Original post by Lewis7253
Did anyone else do the actuvation energy one. Was tricky. Required natural logs and complex rearring. Think i got something like 3.96x10^-20J


Yesss son
Reply 138
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urz13
8
Original post by Rhetorical Hips
For the rate of collision one, I rearranged to find F, then found F exerted per particle by using change in momentum over time equals force, assuming that t=1 second. Then divided F by F exerted per particle. Bit of a messy method I know.

I did the same. Can't remember my answer, but 2.7x10to the something sounds familiar so I'm hopeful!
Could we say that the methods of measurement are more accurate?


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