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AQA A-level Physics Paper 2 (7408/2) - 9th June 2023 [Exam Chat]

hopefully nothing on nuclear radius & density. i was not taught that and i just remembered it exisisted. id say im helping to lower the grade boundaries but i dont think they could be made any lower... fml :redface:

AQA were horrible in Paper 1. If Paper 2 is just as hard then they'll have to lower the boundaries even more so that's reassuring. It's a shame because I prepared so much for Paper 1 just for them to ask stupidly worded and styled questions - nothing of which I've ever seen in any past paper. :nothing:

Reply 81

cerealsnatcher

3

Original post by Ak_5

Can someone explain why the sin (wt) in the second last step just disappears?
I attached a screen shot below

(quoting kingemperor because he/she is really good at explaining but anyone is free to help ofc lol)

I think because it is emf max and the largest sin0 can give is 1

Reply 82

Ak_5

4

Original post by cerealsnatcher

I think because it is emf max and the largest sin0 can give is 1

but why would sin be 0? would it not be 25 because thats the amount of rotations per second?

Reply 83

cerealsnatcher

3

Original post by Ak_5

but why would sin be 0? would it not be 25 because thats the amount of rotations per second?

no like sin(theta) = 1

Reply 84

Ak_5

4

Original post by cerealsnatcher

no like sin(theta) = 1

yes, theta here would be wt, w is 25 and t is 1, so it would be 25. unless i just fundamentally dont understand

Reply 85

Bruce Wayne59875

6

Original post by Ak_5

Can someone explain why the sin (wt) in the second last step just disappears?
I attached a screen shot below

(quoting kingemperor because he/she is really good at explaining but anyone is free to help ofc lol)

When looking for maximum emf, it's always useful to consider the component of B which is 90 degrees to the surface of the coil. So when this angle rises to 90 degrees, sin 90 becomes one. Also, the maximum value of sin angle = 1 anyway. So whenever you need to find max emf, just make sin theta 1 - so it disappears.

hope this helped

(edited 10 months ago)

Reply 86

cerealsnatcher

3

Original post by Ak_5

yes, theta here would be wt, w is 25 and t is 1, so it would be 25. unless i just fundamentally dont understand

brother you asked why it disappears i think because it wants max emf, the max value sin(theta) can return is 1 so it would just dissapear no?

Reply 87

Polp

12

Yall i reckon this paper gonna have more written qs but it could be another more problem solving oriented paper cause its aqa. But if it is more written i think there will be some good questions on nuclear reactors and fission and fusion process. Or talking about control rods.

Reply 88

Ak_5

4

Original post by Bruce Wayne59875

When looking for maximum emf, it's always useful to remember that this will occur when the field lines and the surface of the coil are *parallel to one another.
In other words, the angle at between the two is 90 degrees so sin(90) = 1. So the sin(wt) just disappears.

hope this helped

ahhh okay thank you

Reply 89

Ak_5

4

Original post by cerealsnatcher

brother you asked why it disappears i think because it wants max emf, the max value sin(theta) can return is 1 so it would just dissapear no?