AQA A Level Physics Paper 1 7408/1 - 04 June 2018 [Exam Discussion]

Original post by G.Y

And derivation of dsin theta = n lamda

It’s given in the formula booklet but you need to know the derivation

yh it's fairly simple. just a bit of trig really.

Reply 182

gcsemusicsucks

Original post by G.Y

And derivation of dsin theta = n lamda

It’s given in the formula booklet but you need to know the derivation

do we really? :bawling:

Reply 183

Original post by BTAnonymous

Something I learned today was the maximum order is equal to the 'diffraction grating/the wavelength' or 'd/lambda'.

Maximum number of Maxima is 2n+1 (+1 comes from central Maxima).

what is here in the number of maxima one?
With the top one I guess its just sin 90 =1 and past that itlle go behind the grating. note you will always have to round down right?

Reply 184

Original post by yusyus

what is here in the number of maxima one?
With the top one I guess its just sin 90 =1 and past that itlle go behind the grating. note you will always have to round down right?

thats what it essentially is because what is sin of 90? 1. so you get d = n * lambda and then divide by lambda to get the equation.

it's just a little equation which might be handy if it comes up.

Reply 185

Original post by BTAnonymous

thats what it essentially is because what is sin of 90? 1. so you get d = n * lambda and then divide by lambda to get the equation.

it's just a little equation which might be handy if it comes up.

yeah, what is n in the number of maxima one though?

Reply 186

Original post by yusyus

yeah, what is n in the number of maxima one though?

n is just the order of Maxima. Ie, how many Maxima away from the central Maxima. it's the same as d sin theta = n lambda but since we want the maximum number of Maxima which can be viewed, let theta = 90 so therefore

d sin90 = n lambda --> d = n lambda --> d/n = lambda

hence the equation the maximum number of Maxima which can be viewed for a certain wavelength.

(edited 5 years ago)

Reply 187

JZ7800

3

How long do people normally leave for the multiple choice section? I usually leave about 30 minutes (just over a minute for a mark) but tend to run out of time on the last questions.

Reply 188

Original post by BTAnonymous

n is just the order of Maxima. Ie, how many Maxima away from the central Maxima

I mean you wrote maximum number of maxima is 2n+1.
Is that for double slit or something else? what's n in that? ik n in diffraction grating is the order

Reply 189

Original post by JZ7800

How long do people normally leave for the multiple choice section? I usually leave about 30 minutes (just over a minute for a mark) but tend to run out of time on the last questions.

yeah same. time is difficult now because I spend a lot of time reading the questions.

my thinking is that if I take a little more time to ensure I don't make a big calculation error which can f*** up a whole question, then missing the last 3-4 multiple choice questions isn't a big deal if I score a majority of marks for the big questions

Reply 190

Original post by yusyus

I mean you wrote maximum number of maxima is 2n+1.
Is that for double slit or something else? what's n in that? ik n in diffraction grating is the order

oh that. if you have the textbook it's on page 86. n is just the greatest maxima observed.

it's common sense if you think about it because the 2n indicates that there are Maxima on both sides of the central Maxima and the +1 takes into account the central Maxima, hence you can find the number of Maxima observed.

Reply 191

G.Y

16

Original post by yusyus

I mean you wrote maximum number of maxima is 2n+1.
Is that for double slit or something else? what's n in that? ik n in diffraction grating is the order

It’s still for the order of a diffraction grating

Reply 192

https://www.thestudentroom.co.uk/showthread.php?t=5367776

Original post by BTAnonymous

oh that. if you have the textbook it's on page 86. n is just the greatest maxima observed.

it's common sense if you think about it because the 2n indicates that there are Maxima on both sides of the central Maxima and the +1 takes into account the central Maxima, hence you can find the number of Maxima observed.

ahh just never seen it before but yeah it makes sense. Not sure if I have the same textbook (although ive lost mine anyway) but could be a good shortcut if it comes up.
btw im currently looking for harder electricity questions - do you have any reccomendations?

Reply 193

Black-Photon

9

Reply 194

Black-Photon

9

Original post by yusyus

ahh just never seen it before but yeah it makes sense. Not sure if I have the same textbook (although ive lost mine anyway) but could be a good shortcut if it comes up.
btw im currently looking for harder electricity questions - do you have any reccomendations?

You are, are you? Here's one of the worst questions from AS Paper 1 May 2018:
Page 14.jpg

Attachment not found

Ignore the answers I attempted and enjoy.

Original post by Black-Photon

You are, are you? Here's one of the worst questions from AS Paper 1 May 2018:
Page 14.jpg

Attachment not found

Ignore the answers I attempted and enjoy.

Need mark scheme for this or else trying this will create more confusion.

Reply 196

Original post by Black-Photon

You are, are you? Here's one of the worst questions from AS Paper 1 May 2018:
Page 14.jpg

Attachment not found

Ignore the answers I attempted and enjoy.

this does look hard haha ill try it

Reply 197

Black-Photon

9

Original post by yusyus

this does look hard haha ill try it

Original post by Lawlerfhfbdj

Need mark scheme for this or else trying this will create more confusion.

Good luck! As so new there's no official mark scheme, but it's Question 6 on the unofficial mark scheme here.

Reply 198

Original post by yusyus

ahh just never seen it before but yeah it makes sense. Not sure if I have the same textbook (although ive lost mine anyway) but could be a good shortcut if it comes up.
btw im currently looking for harder electricity questions - do you have any reccomendations?

ooooh electricity. I used to suck at that so much but I'm more confident now.

If youve done most of the past papers in the last 8-10 years then I don't know any hard electricity questions sorry.

I think the hardest type they could throw is a tricky potential divider question imo.

Reply 199