AQA Physics PHYA5 - Thursday 18th June 2015 [Exam Discussion Thread]

Reply 1760

Klaxoii

2

ImageUploadedByStudent Room1434394645.908944.jpg

Can someone check that this a correct diagram of an E/M wave, thanks!

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Reply 1761

gcsestuff

2

Original post by Klaxoii

Can someone check that this a correct diagram of an E/M wave, thanks!

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Spot on. I would try to put little right angles on the diagram just to be 100%

Another thing is that electric and magnetic fields are of equal magnitude :smile:

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Reply 1762

ChiefKeef

1

Yooooooo do we need to know how to derive those total kinetic energy equations

Reply 1763

Klaxoii

2

Original post by gcsestuff

Spot on. I would try to put little right angles on the diagram just to be 100%

Another thing is that electric and magnetic fields are of equal magnitude :smile:

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Thanks dude!

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Reply 1764

gcsestuff

2

Original post by Klaxoii

Thanks dude!

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I think radio waves and em waves etc will come up this year and there isn't much they can ask I don't think so just make sure you do that question about the radio wave being polarised

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Reply 1765

Mai.H

7

Original post by ChiefKeef

Yooooooo do we need to know how to derive those total kinetic energy equations

I think we do so my teacher says anyway altho ive never seen a question on it :confused:

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Reply 1766

CD223

OP

10

Original post by ChiefKeef

Yooooooo do we need to know how to derive those total kinetic energy equations

By total kinetic energy do you mean

[br]\dfrac{3}{2} NkT[br]

?

I've only ever seen this used?

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Reply 1767

gcsestuff

2

Can anyone post a simple derivation of the kinetic model

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Reply 1768

TheBeardedGuy

1

Original post by gcsestuff

Can anyone post a simple derivation of the kinetic model

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Assumptions in order to establish a kinetic theory for an ideal gas:

• Collisions between molecules and the walls of the container are elastic.
• Intermolecular forces are negligible except during a collision.
• Energy is only kinetic and not stored as potential.
• The volume occupied by the molecules is negligible in comparison to the volume of the container.
• Time spent in collision is negligible when compared to time spent between collisions.
• Molecules are in continuous random motion.

Hope this helps!

Reply 1769

Absent Agent

21

Original post by TheBeardedGuy

Assumptions in order to establish a kinetic theory for an ideal gas:

• Collisions between molecules and the walls of the container are elastic.
• Intermolecular forces are negligible except during a collision.
• Energy is only kinetic and not stored as potential.
• The volume occupied by the molecules is negligible in comparison to the volume of the container.
• Time spent in collision is negligible when compared to time spent between collisions.
• Molecules are in continuous random motion.

Hope this helps!

That's great :smile:

. Though sometimes we are expected to explain why a particular assumption is made. I've got a written note on them. If you haven't then i will write them out on here

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