Bozo's queries

[cranberry]

Just one question from Insight 2009, the solution can't be right!!??

Im 99.99967% sure that the left side is the south pole as current flows clockwise (from the positive terminal)!?

Any one else agree?

[Prizate]

Yeah. I think they have got it wrong. Using the right hand grip rule with the current being your fingers and the magnetic field direction being your thumb shows that the north end will be the right-hand side and the left will be the south. This is the only thing i can think of. Actually, if you look at the solution image, the left wire if going over the magnet, maybe they got confused with this. Which is ridiculous because the other end is also on top of the magnet. Hope this helps.

[b^3]

I've got a feeling what I'm about to say is wrong, but it's something to think about. The magnetic field that is produced by the current carrying wire will be north Q, to P south. But wouldn't this field cause a change in flux in the electromagnet, using lenz's law the electromagnet will try to oppose this change in flux producing a magnetic field in the opposite direction? So the field that the elctromagnet is expirencing is from north P to Q south?

I think I may be wrong, but it kinda makes sense. Anyone got anything to add (laserred)?

[xZero]

I've got a feeling what I'm about to say is wrong, but it's something to think about. The magnetic field that is produced by the current carrying wire will be north Q, to P south. But wouldn't this field cause a change in flux in the electromagnet, using lenz's law the electromagnet will try to oppose this change in flux producing a magnetic field in the opposite direction? So the field that the elctromagnet is expirencing is from north P to Q south?

I think I may be wrong, but it kinda makes sense. Anyone got anything to add (laserred)?

lets suppose that you're right, but after like 0.1 sec of switching the current on, there won't be any change in flux so the 'magnetic field' thats trying to oppose the change will disappear and the only magnetic field left would be from the current

[b^3]

I've got a feeling what I'm about to say is wrong, but it's something to think about. The magnetic field that is produced by the current carrying wire will be north Q, to P south. But wouldn't this field cause a change in flux in the electromagnet, using lenz's law the electromagnet will try to oppose this change in flux producing a magnetic field in the opposite direction? So the field that the elctromagnet is expirencing is from north P to Q south?

I think I may be wrong, but it kinda makes sense. Anyone got anything to add (laserred)?

lets suppose that you're right, but after like 0.1 sec of switching the current on, there won't be any change in flux so the 'magnetic field' thats trying to oppose the change will disappear and the only magnetic field left would be from the current

Yeh I thought of that about 5 mins after I posted but was trying to make the stupid question work. How would you go about ansering it xZero? Do you think they are wrong or how do you explain electromagnets (this is an area I'm hazy on and need to work on)

[Bozo]

I think b^3 is correct, because this isn't a solenoid.

[paulsterio]

Considering it's Insight, I think they're wrong! D:

[b^3]

Yeh now that I realise it's insight, they are probably wrong. I hate the way the whole year 12 physics is set up, it's like nothing is set in stone and changes depending on the textbook you read or the exam you pick up. Can't wait to finish VCE, Only one day to go!

[xZero]

yeah imma say that its wrong, and b^3, just wait till uni physics, you'll be crying so hard that you wish you're still doing VCE physics (although i dont miss vce maths at all)

[paulsterio]

Yeh now that I realise it's insight, they are probably wrong. I hate the way the whole year 12 physics is set up, it's like nothing is set in stone and changes depending on the textbook you read or the exam you pick up. Can't wait to finish VCE, Only one day to go!

Off topic, but yeah, I agree with you, plus none of the VCE Physics textbooks seem to contain all the material you actually need in order to do exams! D:
Most of them don't even have all the formulas and somehow you're given these massive paragraphs of text that are completely irrelevant to the course and are just beating around the bush
Makes studying for Physics hard, I just use iTute and my teacher's notes now

[Lasercookie]

Hmm... I think I know what Insight have done.

They've gone the fingers is the direction of the wires (clockwise/anticlockwise) and then the thumb indicates north. I learnt this one at the Connect lecture - personally it confuses me because I keep thinking that the thumb becomes the direction of the field (I prefer to stick with current = thumb, fingers=field). I think Insight made this mistake - they forgot that the field direction on the inside is North to South.

That's my guess anyway.

Using the way I would do the question - I'd pick one line of wire. I then figure out the current direction - "down" in this case. Then I use the RH Grip rule (thumb = current) and use that to figure out the field. Which is P to Q.

[b^3]

yeah imma say that its wrong, and b^3, just wait till uni physics, you'll be crying so hard that you wish you're still doing VCE physics (although i dont miss vce maths at all)

I'm hoping you're not saying that uni physics is more ambiguous than VCE physics . I'll have engineering maths to keep me sane then .

[xZero]

yeah imma say that its wrong, and b^3, just wait till uni physics, you'll be crying so hard that you wish you're still doing VCE physics (although i dont miss vce maths at all)

I'm hoping you're not saying that uni physics is more ambiguous than VCE physics . I'll have engineering maths to keep me sane then .

well its not ambiguous at all, infact the exam is so god damn hard that they had to scale everyone up, almost everyone failed mid sem test, 8am start for first years and the fact that you have to learn 4 different topics in a semister from shitty lecturers (susan... pray that you dont have her) makes VCE physics much more appealing.

[Bozo]

Hey xZero, out of curiosity, do you know for your physics GA's last year whether your mid years was low A or high A and whether your A+ was low or high?

[xZero]

I know that my mid year was a high A (1 mark off A+) but im not sure about end of year, it should be a low A+