Question

Magnetism

What types of poles are there and how do they interact?

Explain three situations in which a magnetic force will interact. (hint: two poles, current carrying wire, moving

charge)

What affects the induced current of a coil in a magnetic field?

Answer 1

What types of poles are there and how do they interact?

Magnetic poles are the ends of a magnet where the magnetic force is strongest. There are two, north and south. The north end of a magnet would come together with the south end of another magnet. But, two like poles wouldn't. It's like when you were a kid, trying to force two magnets together, and your hands were pushed out of the way by the force.

Explain three situations in which a magnetic force will interact. (hint: two poles, current carrying wire, moving

charge)

a.CURRENT CARRYING WIRE

ELECTRICITY AND MAGNETISM ARE 2 SIDES OF THE SAME COIN!!!

ELECTRICITY AND MAGNETISM ARE SOUL MATES RUNNING PERPENDICULAR TO EACH OTHER, AND IN-SYNC.

WHEN ONE MOVES CLOCKWISE, THE OTHER MOVES ALONG A LINE PERPENDICULAR TO THE PLANE OF THE CIRCLE AND THRU THE CENTER OF THE CIRCLE!!

ONE DOES NOT EXIST WITHOUT THE OTHER, WAITING NEARBY.AS SOON AS ONE MOVES, THE OTHER IS BORN AND MOVING!

b. ELECTRONS IN IRON

In the presence of a magnetic field, these free electrons in groups of atoms called domains will align themselves so they are all orbiting the same direction. This produces a miniature magnet. In an iron rod that is not magnetized, these domains are aligned randomly. When you drag a weak magnet from the N pole of a strong magnet towards the south pole of the strong magnet, the strong magnetic field will force these domains to align parallel to the magnetic field of the strong magnet. Now the iron rod is a magnet.

c.MOVING CHARGE

Now, special relativity says that the particle will also not accelerate if viewed from a rocket moving past the line to the right at constant speed V. Special relativity also says that, in this frame, the relative motion of the charges and the rocket causes the negative charges moving to the left to be length-contracted, while the positive charges moving to the right will be length-expanded. This result comes simply from the relativistic law of velocity addition and the law of length contraction.So, in any given piece of space in the rocket frame, there is now more negative charge, and less positive charge, than it had in the lab frame. This charge excess will repel the electron. It seems as though the particle should now feel a net force, which we created simply by switching frames!This cannot be, however, since relativity says both frames are valid points of view, and should agree on observed events (that is, the electron doesn't accelerate towards or away from the line!). To resolve the paradox, there must be a new force, which only occurs when the electron is moving past a current (as it is, in the rocket frame, but is not, in the lab frame). So, we say that currents set up magnetic fields, with which moving charges interact via the Lorentz force.This argument can be made mathematical; you can find an exact treatment in many undergraduate textbooks on electricity and magnetism. To summarize, the laws of relativity and basic electrostatic forces show that we need a new, motion-dependent force in order for our laws to be consistent.

What affects the induced current of a coil in a magnetic field?

There are therefore three ways an emf can be induced in a loop:

1.Change the magnetic field

2.Change the area of the loop

3.Change the angle between the field and the loop