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The Physics PHYA2 thread! 5th June 2013

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Reply 1460

StalkeR47

Original post by Micheal123456

When mentioning that kinetic energy is converted In to gpe what else should u mention?

GPE is dependent on mass and the height because gpe=mgh. Mention that too. :smile:

Reply 1461

Micheal123456

Could someone run through polarisation please

Reply 1462

Felix Ivers

You know what, it really wouldn't surprise me if they just decided to change it to a 9 marker just to be real see u next Tuesdays.

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Reply 1463

SortYourLife

On a stationary wave:

Nodes are where the wave and reflected wave are antiphase
Antinodes are where the two waves are in phase

Is that right? All this time I've been thinking its the other way round!

Really hope the 6 marker is to describe an experiment to determine the Young's modulus......

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Reply 1464

Jack93o

Original post by StalkeR47

ok. Lets see if people can answer this question. It is quiet a bad question to come in the exam tomorrow. I did appear before I remember. Q: Distinguish between stationary and progressive waves. :smile:

stationary wave to not transfer energy, whereas progressive waves do

Reply 1465

Felix Ivers

If there's a question like: a ball is dropped from a cliff 16 metres above the ground. How long does it take to hit the ground? Give your answer to an appropriate number of sf's. Would you give it to 2 or 3?

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Reply 1466

amujamu

What experiment u guys think is coming up?

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Reply 1467

_JasmineMistry

Original post by Felix Ivers

2. look at the question, if in doubt use 3

Reply 1468

task

could someone please explain June 2010 question 7c to me please? it's only one mark but I really don't understand how to get the answer thanks

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Reply 1469

Micheal123456

Original post by task

could someone please explain June 2010 question 7c to me please? it's only one mark but I really don't understand how to get the answer thanks

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Also 7d

Reply 1470

v.007

Original post by kinglj81

Hi guys can you help me with something..

I was wondering what you do for questions about slits and diffraction that say show what you see on the screen. Do you draw the intensity graph type thing or just band or dots

Also when you diffract white light through a grating how do you show that the inner side is violet and the outer is red. Is this done on the intensity graph?.

Anyone??

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Reply 1471

Jack93o

Original post by v.007

Anyone??

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I think you would just label the colours, you don't have to label all of them, just blue/violet on one side and red on the other side of the fringe

Reply 1472

StalkeR47

Hello guys! I am awake! So, if you need help just ask. :smile:

Reply 1473

StalkeR47

I am available till 7am. You have 1 more hour left to ask for help.

Reply 1474

Talon279

Original post by StalkeR47

I am available till 7am. You have 1 more hour left to ask for help.

Is there anything in your opinion that will DEFINITELY come up? I don't mean in general, I mean anything specific :smile:

Reply 1475

SAS18

Original post by StalkeR47

Hello guys! I am awake! So, if you need help just ask. :smile:

morning! what is torque?

Reply 1476

StalkeR47

Original post by Talon279

Is there anything in your opinion that will DEFINITELY come up? I don't mean in general, I mean anything specific :smile:

well. It is hard to say but waves (transverse/progressive and stationary wave) might come up. Newton's law questions might come up. And, questions on refraction and reflection has always come up in the end so this could be another one eg, core-cladding fiber optic question. question on spring constant (parallel and in series) might come up as well. And finally, I am guessing a 6-marker to be an unexpected question like the one with unit 1.

Reply 1477

StalkeR47

Original post by SAS18

morning! what is torque?

The moment of a couple (opposite forces on the object on either sides parallel to each other) is referred to a torque.

Reply 1478

OliverG

Original post by Felix Ivers

Felix! Revising at 1AM? Shame on you.

The question gives 2sf, so your answer is in 2sf. If it said 16.0m, it would be to 3sf.

Reply 1479

StalkeR47

Few points guys I made while doing the revision. Diffraction: is the spreading of waves when they pass through a gap or by an edge. Waves will spread more if; 1) the slit spacing is made narrower (intensity will be reduced), 2) the wavelength is made larger. dsintheta=n lambds is the equation for diffraction grating- maximum number of orders is given by d=n=d/lambda. Remember: Convert everything into m. If you are given a grating has 300 lines per mm, find how much it is for 1 line per m. so, 1/300x10^3 will give length of 1 line per m. dsintheta=n lambds (d=slit spacing, theta=fringe angle, n=order of peak. Double slit (young's modulus) is known as coherent since they emit waves with a constant phase difference and same frequency. Light from nearby sources will not produce an interference pattern because they emit waves at random position so constructive/destructive pattern could not be formed. Red light has the longest wavelength and the shortest frequency (opposite for blue light). Longer wavelength=grater fringe separation (since w=lambda D/s). Actually it is a lot more. It will take ages and I should have done it before. Sorry.