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The Physics PHYA2 thread! 5th June 2013

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please help! i seem to be losing marks on all of the equations that involve trigonometry rules. I remember s=o/h c=a/h t=o/a from maths and am confident with this but seem to be using the wrong one (mixing up between sin and cos)
e.g. jan 2013 - q 2 b i, i am conviced you have to use cos but the mark scheme says sin?! why is it sin and not cos?
thaaaanks!!

Hi! Just remember this. To find Adjacent (in a right angle triangle) use cos. To find opposite, use sin. Is that ok? :smile:

Reply 781

Jimmy20002012

Original post by StalkeR47

Hi! Just remember this. To find Adjacent (in a right angle triangle) use cos. To find opposite, use sin. Is that ok? :smile:

Hey how do you know when partial internalreflection occurs?

Posted from TSR Mobile

Reply 782

StalkeR47

Does anyone need any help?

Reply 783

StalkeR47

Original post by Jimmy20002012

L

Hey how do you know when partial internalreflection occurs?

Posted from TSR Mobile

It always does. Partial means little/half. :smile:

Reply 784

BigBadJFly

Original post by Jimmy20002012

L

Hey how do you know when partial internalreflection occurs?

Posted from TSR Mobile

when the angle of incidence is equal to the critical angle

Reply 785

x-Sophie-x

Original post by StalkeR47

Sorry, I just ate my crappy chicken wraps. :biggrin:

I am very confident for the exam. Just had ICT exam today. And, sorry, I have never posted anything on the biology section chemistry section. But yeah, maths physics a lot of times. :smile:

Awh, I thought you were looking forward to them xD
How did ICT go? :')
Oh right, must just be Physics then! That's weird :L

Reply 786

StalkeR47

[QUOTE="Jimmy20002012;42964251"]L

Hey how do you know when partial internalreflection occurs?

Posted from TSR Mobile[/QUOTE
Partial internal reflection always occurs at a boundary when the angle of incidence is less than or equal to the critical angle.

Reply 787

TheSnail

That's chemistry done now for this one - my last exam.

They certainly saved the best til' last *heavy sarcasm intended*

Reply 788

StalkeR47

Original post by BigBadJFly

when the angle of incidence is equal to the critical angle

Equal or less than the critical angle. :smile:

Reply 789

StalkeR47

Original post by x-Sophie-x

Awh, I thought you were looking forward to them xD
How did ICT go? :')
Oh right, must just be Physics then! That's weird :L

HI! I was looking forward to them but found out that they were crap. HAHA. ICT was a doddle. :smile:

Reply 790

BigBadJFly

Original post by StalkeR47

Equal or less than the critical angle. :smile:

But when we have to draw the light path on a diagram, you only do both if the angle of incidence is equal to the critical angle - that's all we're expected to know for the exam (I think).

Reply 791

x-Sophie-x

Original post by StalkeR47

HI! I was looking forward to them but found out that they were crap. HAHA. ICT was a doddle. :smile:

Haa :L
That's good xD
Can't say any of my exams were 'a doddle' haha.

Reply 792

StalkeR47

Original post by BigBadJFly

But when we have to draw the light path on a diagram, you only do both if the angle of incidence is equal to the critical angle - that's all we're expected to know for the exam (I think).

Amm.. In my revision book, it says partial internal reflection occurs when incident angle is less than or equal to the critical angle. I have nelson thornes and it is for AQA exam board only. :smile:

Reply 793

h94k

Can someone show me how to draw Jan 2011, 3E pleasee

Reply 794

StalkeR47

Original post by x-Sophie-x

Haa :L
That's good xD
Can't say any of my exams were 'a doddle' haha.

My sociology exam was definitely a flow. I had that exam on the same day as maths so I focused 99.9999% on c1 c2 and 0.00001% on sociology. HA. I failed it. Definitely. :angry:

Reply 795

StalkeR47

Original post by h94k

Can someone show me how to draw Jan 2011, 3E pleasee

Draw a rectangular screen. And on it, draw a fringe pattern. Make sure middle one is more bright and label min max. etc. :smile:

Reply 796

Jack93o

Original post by BigBadJFly

when the angle of incidence is equal to the critical angle

so you would only get partial reflection if the angle of incidence is exactly equal to the critical angle?

what if the ray is refracted through, do you still get a bit of reflection?

Reply 797

StalkeR47

Original post by h94k

Can someone show me how to draw Jan 2011, 3E pleasee

like this! The bottom spectrum. :smile:

Reply 798

h94k

Original post by StalkeR47

Draw a rectangular screen. And on it, draw a fringe pattern. Make sure middle one is more bright and label min max. etc. :smile:

Are there different colours?

Reply 799

x-Sophie-x

Original post by StalkeR47

My sociology exam was definitely a flow. I had that exam on the same day as maths so I focused 99.9999% on c1 c2 and 0.00001% on sociology. HA. I failed it. Definitely. :angry:

I'm not the only one then >.<

Could anybody help me structure an answer to this please?

"Describe the necessary procedure in order to obtain an accurate and reliable value for the wavelength of the laser light. Your answer should include details of all the measurements and necessary calculations"