1) The north pole of a magnet is brought near an unmagnetized solid ball of conducting metal hanging by a string. The ball is highly attracted to the north pole. When the magnet is taken away and the south pole is brought near the ball, does it...
Options..etc.etc.. (I think it is, again, strongly attracted to the magnet, am I correct)
2) Light goes from air into a denser medium, let's say glass. Which variable stays constant?
Frequency, Wavelength, or Speed?
I said Frequency.

Question

1) The north pole of a magnet is brought near an unmagnetized solid ball of conducting metal hanging by a string.  The ball is highly attracted to the north pole.  When the magnet is taken away and the south pole is brought near the ball, does it...
Options..etc.etc.. (I think it is, again, strongly attracted to the magnet, am I correct)
2)  Light goes from air into a denser medium, let's say glass.  Which variable stays constant?
Frequency, Wavelength, or Speed?
I said Frequency.

ujjwal · Answer

For second one you are correct.. it's frequency..
For first one can you list the options. If not tell me do you know anything about hysteresis?

anonymous · Answer

If I remember correctly, the other options were:
-The ball is weakly attracted to the south pole
- The ball is strongly opposed
-Weakly opposed
I think the idea is that since the ball isn't magnetized, it will be attracted regardless of pole. (Kind of like a pith ball to a negative or positive charge)

ujjwal · Answer

the ball must be slightly magnetized.. so, the most appropriate option according to me will be "weakly attracted to south pole" .. however this also depends upon hysteresis and nature of metal used..

anonymous · Answer

The problem specifically states it isn't magnetized.  Why must a metal ball be magnetized to be attracted to a magnet?  Not all pieces of metal attracted to common table magnets are magnetized (I realize their atoms are polar, but that's different)

anonymous · Answer

My bad, not atoms are polar, electrons are free*

ujjwal · Answer

At least it is temporarily magnetized..

anonymous · Answer

The ball never contacts the north pole of the magnet (I believe).  Now that I think about it the problem never stated...

anonymous · Answer

Ah I just found a solution to a different test online, similar question - http://www.phy.syr.edu/~xxing/teaching/phy212/Workshops/solutions/WS_11.1_sol.pdf Problem 2

anonymous · Answer

The ball need not be in contact with magnet to get magnetised

ujjwal · Answer

The magnet will induce magnetism in the magnetic material. That is, the magnetic field of the other magnet will temporarily convert the magnetic material into a magnet.

anonymous · Answer

shivam I've answered the original question, but now you've got me curious about magnetization through induction.  I understand giving charge to conductors through induction/grounding...can the same be done with magnetism? If you wouldn't mind elaborating.

anonymous · Answer

Another answer to problem 1 online - http://answers.yahoo.com/question/index?qid=20080515095439AAyeBfx

anonymous · Answer

@robertsto , adding to @ujjwal's point, The magnets which have high retentivity, tend to remain magnetised while some materials, easily become magnets and also lose their magnetic property easily (electromagnets) . I would suggest you go through hysteris curve to understand this

ujjwal · Answer

@robertsto Do you know anything about hysteresis? If no, take time to view this.. http://hyperphysics.phy-astr.gsu.edu/hbase/solids/hyst.html It has something to do with your question.. Well if you haven't even heard the word "hysteresis" .. the answer will be "strongly attracted"...