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VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: iGoRaw on October 12, 2013, 06:45:09 pm

Title: Magnetic field lines around Solenoids
Post by: iGoRaw on October 12, 2013, 06:45:09 pm: Hello
I've always been taught take the direction of the current and see if you can make the letter N or S. If you can make an N, that is the north pole and then draw the magnetic field lines going from that pole to the other (N to S). Now that i've done a couple of questions on this, i've come to find out that there are opposing viewpoints on this or something? Am i doing something wrong? VCAA answers on a question like this follows the rule i meantioned earlier. Kilbaha on the other hand draw the field lines in the opposite direction.
A quick 'magnetic field lines around a solenoid' google search confirms this conflict.
Help?

Edit 1: Nvm... i get it.
It just depends upon whether the electric line goes over or under...
I answered my own question. lol

Edit 2: Guess VCAA have been kind to students so far as in not tricking students by drawing the current going over and under. As in out of the page then into the page.
God.. it's difficult explaining magnetism on paper.
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Mod Edit - Merged triple post (Snow Red)
Title: Re: Magnetic field lines around Solenoids
Post by: BigAl on October 12, 2013, 07:27:10 pm: I follow the current. the point where I leave the solenoid is N.
Title: Re: Magnetic field lines around Solenoids
Post by: angus_grant on October 30, 2013, 05:45:09 pm: Hi iGoRaw,
I know you said you fixed it, but just use the RHSolenoid rule to find where the North pole is (wrap fingers with current, then thumb points to North pole). field lines then go through the solenoid to the North pole. First time ive heard of trying to make the letter N, sounds interesting haha. Well hope that helped!
ps. Left handers rule at physics as they can write and use the right hand rule simultaneously 8)
Title: Re: Magnetic field lines around Solenoids
Post by: Spammingb on November 12, 2013, 03:38:41 pm: Quote from: BigAl on October 12, 2013, 07:27:10 pm
I follow the current. the point where I leave the solenoid is N.

This confused me for a little while, but I don't think this is always the case. Check out VCAA 2012 Qu 1.
Title: Re: Magnetic field lines around Solenoids
Post by: BigAl on November 12, 2013, 06:11:42 pm: Quote from: Spammingb on November 12, 2013, 03:38:41 pm
This confused me for a little while, but I don't think this is always the case. Check out VCAA 2012 Qu 1.
I wasn't very clear there..this photo may help.
Title: Re: Magnetic field lines around Solenoids
Post by: availn on November 12, 2013, 06:59:12 pm: Quote from: BigAl on November 12, 2013, 06:11:42 pm
I wasn't very clear there..this photo may help.

Were you saying that the end where the current leaves the coil is north? Because that is not true, if the current was flowing in the same direction, but the coil was wound the other way, north would be at the end where the current enters.