Physics Exam Thoughts (1 Viewer)

pikachu975

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For the maglev train superconductors one what'd people write
 

NinjaDatHSC

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i wrote it could carry large currents cause no resistance below critical temp and it is cheaper to run than conventional electromagnets cause no resistance meant not as much energy loss due to heat maybe that's the same point tho
 

camstu

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Idk if it will let me say the site name on this without getting banned. It's just in hsc exam discussion 2017 for another site if you look for it you'll find it
found it thanks, according to that I got 17/20 in MC, not great but seems everyone had their problems in it so its ok i guess
 

blinkandyoullmissit

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i wrote it could carry large currents cause no resistance below critical temp and it is cheaper to run than conventional electromagnets cause no resistance meant not as much energy loss due to heat maybe that's the same point tho
They don't use the meissner effect to levitate the train
 

NinjaDatHSC

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Yeah i didn't say that in my answer. But to levitate it, don't they use repulsion by using the same pole on the train and on the tracks?
 

blinkandyoullmissit

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Yeah i didn't say that in my answer. But to levitate it, don't they use repulsion by using the same pole on the train and on the tracks?
yeah with rapidly changing electromagnets.

like positive pole on the train, positive behind the train (repulsion) then negative infront (attraction) to make it efficient
 

janzrn

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The radiation question was bs had no clue what I was writing
Proton I half bsed it but hopefully my north west helical shape was right

To the person above, range was found using delta y = 0, finding t and subbing back into delta x.
Pre sure from the top, the proton is moving in a parabola instead of north west
 

Asylum99

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Anyone know what the band 5 cut off will be? Asking for a friend
 

pikachu975

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Why are different frequencies used for Sector (3.5MHz) and B (20MHz) scans?

Also, the polarity of P and Q? I got P as positive and Q as negative? Correct or nah?
I put that too but P is negative turns out since it said "circuit" hence positive charges come out of the positive terminal. If it was just a wire it'd be P but nah
 

fluffchuck

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Why are different frequencies used for Sector (3.5MHz) and B (20MHz) scans?

Also, the polarity of P and Q? I got P as positive and Q as negative? Correct or nah?
I don't completely remember what P and Q were, but the current travels in a clockwise direction.
 

pikachu975

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I don't completely remember what P and Q were, but the current travels in a clockwise direction.
Yeah I thought it was a normal wire so positive charges build up at P but guess it's a circuit so positive charges go to negative (P).
 

blinkandyoullmissit

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Why are different frequencies used for Sector (3.5MHz) and B (20MHz) scans?

Also, the polarity of P and Q? I got P as positive and Q as negative? Correct or nah?
3.5 is used cause it has less interaction with bodily tissue so is used as sector scans imaging e.g. Babies in a mothers womb. Lower energy sound waves interact less with tissue so can "reach" further into the body, but as a result has lower resolution.

20 is used in situations where less penetration is required eg eye scans or other small areas of the body. The higher energy sound waves interact more and thus give a higher resolution image. B (brightness) indicates the size/thickness of a particular layer.
 

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