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AQA A Level Physics Paper 3 7408/3 - 16 Jun 2022 [Exam Chat]

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Original post by d4r
As much as I want that line of best fit to be straight... I do remember the points having a curved shape when I was trying to do a straight line of best fit.
I don't think drawing a straight line of best fit and then reading off that line is worthy of 4 marks, 3 at most. It makes sense that drawing a curved line of best fit then extrapolating would be worth 4, I remember they asked a question exactly like it before.


Oh I messed up then, I knew the 4 marks for that was suspicious...
Original post by d4r
As much as I want that line of best fit to be straight... I do remember the points having a curved shape when I was trying to do a straight line of best fit.
I don't think drawing a straight line of best fit and then reading off that line is worthy of 4 marks, 3 at most. It makes sense that drawing a curved line of best fit then extrapolating would be worth 4, I remember they asked a question exactly like it before.

Someone said max 1 mark if straight line used and i was fuming lmaoo
Reply 582
To prove it wasnt inversely proportional, did people just multiply the pressure and volume for the given data points to see if gave a constant value
Original post by d4r
Did u find the resultant angular displacement and then divide by 12

Yes
Reply 584
Turning points
What did you guys get for that question about whether the gears on the wheel was enough to measure the speed of light. I found a value for f0 as like 12.somethingHz by subbing in the actual speed of light; then I found the frequency of the wheel and that came out as 10.333Hz and because it was just below 12 I said how it wasn’t quite fast enough frequency and hoped it worked?
I didn’t really know what I was doing but the results were so close it seemed right?
Reply 585
Original post by d4r
As much as I want that line of best fit to be straight... I do remember the points having a curved shape when I was trying to do a straight line of best fit.
I don't think drawing a straight line of best fit and then reading off that line is worthy of 4 marks, 3 at most. It makes sense that drawing a curved line of best fit then extrapolating would be worth 4, I remember they asked a question exactly like it before.

The line didnt have to pass through all the points plus if you check the mark scheme theres usually two marks for drawing it above and below a certain data point then one for correct mass used and one for answer in range. Because now am thinking about it barring two quantities dont have a relationship they are either inversely proportional or direct. A curve will pass through all data points but a straight line doesnt have to
Original post by d4r
As much as I want that line of best fit to be straight... I do remember the points having a curved shape when I was trying to do a straight line of best fit.
I don't think drawing a straight line of best fit and then reading off that line is worthy of 4 marks, 3 at most. It makes sense that drawing a curved line of best fit then extrapolating would be worth 4, I remember they asked a question exactly like it before.

Hey would y please mind telling me which exam paper did that come up in?
Original post by Moke boi
Tbh I thought it was very ambiguous because I thought it wanted you to draw a str8 line because you proved it was not inversely proportional, but did clearly have some curvature to it, ended up doing a str8 line in the end, whether it was right or wrong I wont know

Surely it would be more curvey if they actually wanted a curve though? Or are AQA that mean? Because yeah the points didn’t all go through a straight line but the central ones did it was only the outer 2 that you had to account for (eg shift line so one point on one side, another on the other side)
Original post by SDx3
Turning points
What did you guys get for that question about whether the gears on the wheel was enough to measure the speed of light. I found a value for f0 as like 12.somethingHz by subbing in the actual speed of light; then I found the frequency of the wheel and that came out as 10.333Hz and because it was just below 12 I said how it wasn’t quite fast enough frequency and hoped it worked?
I didn’t really know what I was doing but the results were so close it seemed right?

yh i got the speed of light out and said it wasnt close, so diff argumeent same conclusion
Reply 589
Original post by Wonkagenius
Someone said max 1 mark if straight line used and i was fuming lmaoo


That was me LOL
I meant because AQA mark schemes are annoying with this kind of thing i.e. when they have a set method to do a question they say that if the student tries the other method they can only get max 1 mark.
Original post by SDx3
Turning points
What did you guys get for that question about whether the gears on the wheel was enough to measure the speed of light. I found a value for f0 as like 12.somethingHz by subbing in the actual speed of light; then I found the frequency of the wheel and that came out as 10.333Hz and because it was just below 12 I said how it wasn’t quite fast enough frequency and hoped it worked?
I didn’t really know what I was doing but the results were so close it seemed right?


Did you divide the number of turns by 60 to get per second?
Oh well. We can all look at the mark scheme in two years and settle this best fit line debate :smile:
For the Boyles law graph where everyone seemed to get 150ish or 2.2 can anyone remember what axis’s the MPa was V was on, and what value they got for the gradient
Original post by d4r
That was me LOL
I meant because AQA mark schemes are annoying with this kind of thing i.e. when they have a set method to do a question they say that if the student tries the other method they can only get max 1 mark.

What q number was this?
Reply 594
Original post by Bobbina
Did you divide the number of turns by 60 to get per second?

Um something like that yh
Original post by bagels2001
For the Boyles law graph where everyone seemed to get 150ish or 2.2 can anyone remember what axis’s the MPa was V was on, and what value they got for the gradient


edit Think it was log(V/MPa)
(edited 1 year ago)
Original post by cata03
Think it was log(v/kPa)

Gradient was about bang on -1
Yea than 1/Ans then just insert the random numbers in. I did that got like 2.something x 10(^8)
Reply 598
Original post by Dejithefat
Gradient was about bang on -1


Ay I got like -1.0375
Original post by cata03
Think it was log(v/kPa)

Yh that’s what I thought, what did everyone get for the gradient i roughly remember getting like -1.033 ish
(edited 1 year ago)

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