Question

Could anyone please explain me this :/

Answer 1

The diagram
http://screencast.com/t/naxx1qNUG

Answer 2

The frequency of the oscillator is now maintained at a constant value. The amplitude of
vibration is found to decrease when the current in the electromagnet is switched on.
Use the laws of electromagnetic induction to explain this observation.

Answer 3

@Vincent-Lyon.Fr @

Answer 4

I believe Lenz's law is at play here. This is how electronic scales slow down the weighing plate holder so that they can read out the value faster.

Answer 5

Eddy currents will appear in the plate by electromagnetic induction and add a drag force to the other forces acting on the plate.
Lenz law says that the force always counteracts the cause of the induction phenomenon. So this force will always oppose relative velocity between the plate and the (electro)magnet, hence slowing it down.

Answer 6

oops im sorry about that ^^^^^^^^

Answer 7

@UnkleRhaukus

Answer 8

@Vincent-Lyon.Fr Why cannot it be like dis, Due to the relative motion of the electromagnet, an EMF is induced in the coil, so according to lenz law, the coil acts so as to opposite the change producing it ( EMF producing) by opposing the force? Does it make sense?

Answer 9

What coil?
The electromagnet is facing the metal plate only.

Answer 10

The aluminium plate does not produce any magnetic field.

Answer 11

sorry my bad,
So due to electromagnetic induction at the aluminium sheet, A force is produced on what?

Answer 12

It is produced on the aluminium sheet itself because it moves in front of the magnetic field.

Answer 13

Ok, so due to the motion of aluminium sheet, according to the elctromagnetic induction a force is produced on the aluminium sheet, which acts so as to oppose the change producing it (motion of aluminium sheet) this opposing force ( force due to electromagntic induction) reduces the motion hence the amplitude decreases

Answer 14

?

Answer 15

Perfectly correct :-)

Answer 16

thanks alot \;0