2003 Hsc - Q20 (1 Viewer)

[sHin]

HSC Physics 2003. Q18
How does the Copper wire in the second solenoid affect the result?

 

[Constip8edSkunk]

lol, i remember this q, i completely screwed it cuz i mis read what it meant...

basically 1st 1 would cause charge separationin the solenoid, so there may be an initail reaction it wouldnt really move with the motor effect as experienced by 2nd 1, which has a closed circuit.

EDIT: a quick search found this thread: http://www.boredofstudies.org/community/showthread.php?t=17485&page=1&pp=15

 

[Jase]

lol post HSC physics stress

 

[xiao1985]

lol, i remember this q, i completely screwed it cuz i mis read what it meant...

basically 1st 1 would cause charge separationin the solenoid, so there may be an initail reaction it wouldnt really move with the motor effect as experienced by 2nd 1, which has a closed circuit.

EDIT: a quick search found this thread: http://www.boredofstudies.org/community/showthread.php?t=17485&page=1&pp=15

can't help myself spammin here: as constrip8ed said...

btw: still can't forget the excitment of post exams... both hsc and first sem exams... =) makin me want to do hsc again =S

 

[t-i-m-m-y]

look in the 2003 HSC physics exam forum.. we were arguing this question. and mr timmy decided to argue against everyone.. 97

 

[Xayma]

Responding to post below me cause Im special
It would act like a laminated coil. The effect would be negligble.

 

[Steven12]

I had a look at the the question, and the thread as well.

Now i understand that first coil will be induced an emf that forms eddy current.
and the second one produce a flow of current which acts as electromagnet.

Now , people in the that thread seem to agree that only second coil will move to the left.
But the first one wont?

why?

when you drop a magnet throu a cylinder, doesnt it experience opposing magnetic created by the eddy current?thus a opposing force slowin it down?

if so, then both coil should move,the magnitude would be determine by which (eddy or normal current) produce the strongest field, isnt that right?

 

[blackbunny]

this question is easy
since it is four marks you have to talk about four thing
in figure 1 no current will be induced because the circuit is not complete
figure 2 will have induce current due to a complete circuit, bu Lenz's law the current set up will oppose what ever created it setting up a North pole.

 

[helper]

Its a good idea to looking at the notes from the markers found at the board site.
For 2003
http://www.boardofstudies.nsw.edu.au/hsc_exams/hsc2003exams/pdf_doc/physics_er_03.pdf


4 Marks
• Fully explains both investigations which could include
– Investigation 1: Since the solenoid is not in a circuit, no current can be
induced by the magnetic field. No current → no induced magnetic field
→ no motion.
– Investigation 2: The circuit is closed, so magnet induces current in
solenoid. Lenz’s law says the current will produce a magnetic field
opposing the changing field that induced it. So direction of induced
field is opposite to field of magnet. They repel, and solenoid moves to
the LEFT. Includes both a description of Lenz’s law and gets direction
of motion correct

3 Marks
• Explains both investigations
• Mentions Lenz’s law OR gets direction of motion correct

2 Marks
• Briefly explains both investigations
OR
• Full explanation of either investigation

1 Mark

• Solenoid moves in investigation 2 but not in investigation 1
OR
• Brief explanation of investigation 1 (no circuit, no motion)
OR
• Brief explanation of investigation 2
OR
• EMF induced in coil 1 because of the motion of the magnet
• OR
• No current produced in coil 1 but is in coil 2