Question

1)A circular loop of wire lies within the horizontal plane, and you are viewing it from above. You hold a magnet above the loop, with its north pole up and south pole down, and you drop the magnet. In what rotational direction will you see the induced current in the loop flow? (clockwise-counterclockwise)

2)The current going through a capacitor is called a (conduction current/displacement current)and arises from changing (electric field/magnetic field)

3) semiconductors are (diamagnetic/ferromagnetic/paramagnetic) materials

4) A circular loop of wire lies within the xy plane. It has an area of LaTeX: 1\:m^21 m 2 and an overall resistance of 4 Ohms. A uniform magnetic field runs in the positive z direction, and its magnitude increases at a rate of 2 T/s. What is the induced current?

Answer 1

1. The magnetic field lines exit from north pole and enter from south pole.

So in this case magnetic field lines are in the upward direction. Now when the magnet falls a current will be induces such that it will resist the magnet by repealing it. So the current has to flow in the clocwise direction such that it will mimic a magnet with south pole up.

2. The current going through is called displacement current and arises from changing electric field.

3. Semiconductors are diamagnetic materials.

4.

The circular loop has an area of

Now from faraday's law, the induced voltage is given by,

Here N is the number of turns in the loop which is 1 in this case. is the magnetic flux, are magnetic field and area of the loop respectively.

Here the area is fixed so,

So the voltage is,

as

So the induced current is, 2/4 Amp=0.5Amp