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

Electric field line always act from positive to negative, so if the electric field in upwards the particle must have a negative charge. I think this is why, but not 100% sure.

I know that's what I thought! But no diagram so I don't get why it would be positive

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Oh right thanks!! One more thing, could you lend me your brain for this exam?

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I suppose you could have my brain, that way you wouldn't be lifeless although you'd still fail physics

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Question 10:
The answer is B.

This is because resonance curves show that a system reaches maximum amplitude (a sharp resonance peak) when the driving frequency equals the natural frequency if the damping is light.



When a system is damped more and more, the amplitude at resonance is reduced and moreover, the resonant frequency is slightly reduced.


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You're a babe! Thank you so much - I'll have a read now

No problem haha! Just hope it helps


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It's great thank you! Just one question - I think I'm being really thick but how do you derive 2Em square root to be the momentum from the kinetic energy equation?

anyone have an easy way of getting their head around fields?? ha ha ha

Anyone care to explain why sharp points produce intense fields?

Is it something to do with:
$[br]E = \dfrac{\Delta V}{\Delta d}[br]$

Where there is a large potential across a small distance?


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Which aspects?


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Doing more than 3 of these 1:45 mins papers per day is brutal lol


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Words won't suffice the reason as to why sharp points produce intense electric fields and I'm not sure about the answer but experimental observations suggest that electric field strength is proportional to charge density, that is charge per unit area. The theoretical understanding of it can seemingly be achieved by Gauss's Law.

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i just cant get my head around them, i dont even know what i dont know

the whole of unit 4 is driving me crazy!!!

Ouch! 3 PHYA4 papers? Or?



Ah! Thank you! Given that it's something we don't need to know, I'm hoping there won't be a question on it aha!


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Yeah, or even the chemistry ones are just horrible.


Hopefully not, but always the examiners find something simple and make it so complicated that cannot be considered physics anymore lol


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