General Thoughts: Physics (1 Viewer)

[silence--]

i think the question just asked for magnitude of force on AB so you didn't need to put a direction

 

[Wight]

Force is a vector quantity...so I put one anyway (that was such a dodgy question)

 

[dinosaurxxx]

Your response on red and blue light? On the relativity of simultaneity question? Force on AB?

The blue and red light:
Because the blue light had more energy per photon, then one watt of red light must be more intense than one watt of blue light. (Ie have more photons in it)

Force on AB:
This was a good question, though there was an angle given, you did not need it as the side AB was actually still perpendicular, and hence it was just F=BILsin90
From memory i think it was 0.1 newtons?

 

[Uzername]

Force on AB:
This was a good question, though there was an angle given, you did not need it as the side AB was actually still perpendicular, and hence it was just F=BILsin90
From memory i think it was 0.1 newtons?

THANK YOU! I was about to change my answer and throw in the Sin45 component... But realised the plane of the side AB was still perpendicular to the magnetic field. Lol... Stuffed up the blue/red light question though

 

[dinosaurxxx]

Also, in that question that asked to show that the net force was zero. guyths! A lot of people in my class got confused! Yes, the forces on the coil cause it to rotate. But don't get confused between TORQUE and FORCE. The force on AB was 0.1 and the force on CD was 0.1 in the opposite direction, hence 0.1 + -0.1 = 0
So the net force is zero, the torque however is not zero.

 

[_deloso]

after English mod B, extension maths and chemistry... you would think that physics would rape us hard!! but that test was relatively easier than the current trend of this year's hsc. wow!!!! 80+ raw hopefully.

 

[Richard Llyod]

This is true! He is my top student, I sometimes thinks he knows too much. It's funny though, he can write a page for a 4 mark answer, showing a logical progression of ideas and communicating ideas clearly, hahaha.

if hes so smart why does he need you? youre stealing his money

 

[damo_g]

does anyone remember a question that asked about the maximum torque on something? I can vaguely remember it but not really. If someone had an answer it might ring a bell.

 

[Fizzy_Cyst]

i just guess the "concise" part of marks won't come directly but as you write more there is more chance of you lacking "coherence" and you could contradict yourself

Agreed. However, when I talked to Margot Braithwaite (Board of Studies Liason Officer), she said the more the students write, the better! As long as they do not contradict themselves, the markers do not look for reasons to 'take marks off', which kind of surprised me.

 

[utanobeiiby]

ok i honestly hate that exam ... it was too easy and will mean that cut off will be high assss!! would prefer it to be harder.... i hate super easy exams! everyone gonna end up getting really high marks which sucks11

 

[FCB]

what was the answer for the electron beam. Was it thermionic emission?

 

[OmmU]

what was the answer for the electron beam. Was it thermionic emission?

Basically yes, but there should have been stuff about high voltage and accelerated towards anode.

 

[FCB]

i think i got confused with a electon gun and i started talking about grids and stuff in tv's etc. Mentioned the anode then crossed it out.

 

[khfreakau]

overall a comparatively easy paper compared to past years. some trippy parts, but nothing that was too bad. i somehow made some stupid calculation error in q18 which lead to me making a silly mistake, and i can't believe i defined parsec wrong... LOL. was not thinking at that part of the test. i had the right definition but i referred to my diagram wrong, header of the gods.

also i thought the astro 7 marker was a bit iffy, but nothing too difficult. the odd question was galileo, didn't see that coming! wasn't too hard if you applied your knowledge though.

 

[jamesfirst]

Basically yes, but there should have been stuff about high voltage and accelerated towards anode.

I said:


- electrons are emitted by thermionic emmsion
- electrodes provide high potential difference
- electrons accelerate due to this potential difference.

 

[_deloso]

I said:


- electrons are emitted by thermionic emmsion correct
- electrodes provide high potential difference by using step up transformers
- electrons accelerate due to this potential difference. electrons accelerate due to anodes

should've also mentioned about collimator to straighten the beams before it goes to the anode

 

[Fizzy_Cyst]

if hes so smart why does he need you? youre stealing his money

I don't tutor him, I teach him at my school

 

[weirdguy99]

should've also mentioned about collimator to straighten the beams before it goes to the anode

I don't know if it was necessary, but I also noted that a second anode could be used to focus the beam. Sometimes electron guns have a second anode to 'brighten' the picture.

 

[bikinigal]

I don't tutor him, I teach him at my school

What school do you teach at?

 

[blackratpoo]

lol yeah what school you at cos i dont like your attitude. imma hunt you down motherfucker.