- #1
jaredvert
- 61
- 0
Then what gives the energy to create this emf?
It is the induced emf in the copper tube correct? It would make a counterclockwise current. But what I don't understand is where is the energy for this induced emf coming from?nsaspook said:What makes the magnetic field change from top to bottom of the tube if we drop a magnet in a copper tube?
jaredvert said:It is the induced emf in the copper tube correct? It would make a counterclockwise current. But what I don't understand is where is the energy for this induced emf coming from?
Yeah I mean I think I get lenz law but can u explain what I'm missing here? The magnet falling induced a counterclowise current in the copper. Where the energy for this emf is what I don't understandUltrafastPED said:See Lenz's Law: http://hyperphysics.phy-astr.gsu.edu/hbase/electric/farlaw.html
jaredvert said:Yeah I mean I think I get lenz law but can u explain what I'm missing here? The magnet falling induced a counterclowise current in the copper. Where the energy for this emf is what I don't understand
Well gravity but I imagine it's acceleration is slower due to the magnetic force exerted on itnsaspook said:What makes the magnet move?
Yes, the person uses energy to pick up the magnet to some height from it's rest position and then release it to fall in the tube due to gravity.jaredvert said:Well gravity but I imagine it's acceleration is slower due to the magnetic force exerted on it
Oh so I see because it has less velocity it's KE is less and so the energy induced to the emf is equal to mgh - 1/2mvf^2. Where vf is velocity in coil. Correct?nsaspook said:Yes, the person uses energy to pick up the magnet to some height from it's rest position and then release it to fall in the tube due to gravity.
http://www.physicsclassroom.com/class/energy/Lesson-1/Potential-Energy
How come when he spins it the magnet accelerates faster down? Is it because the area of the plates perpendicular to the sides are smaller and so smaller current induced?nsaspook said:Judging by the slow speed of the magnet drop in the tube a good percentage of the KE is in the induced emf and it's magnetic field.
jaredvert said:How come when he spins it the magnet accelerates faster down? Is it because the area of the plates perpendicular to the sides are smaller and so smaller current induced?
According to Faraday's Law of Induction, when a magnetic field changes or moves, it creates a moving electric field which in turn produces an electromotive force (emf).
The strength of the emf produced depends on the rate of change of the magnetic field, the number of turns in the wire, and the strength of the magnetic field.
No, an emf can only be produced when there is a change in the magnetic field. A constant magnetic field will not produce an emf.
The direction of the induced emf is determined by Lenz's Law, which states that the induced current will flow in a direction that opposes the change in the magnetic field.
Emf production from changing magnetic fields is used in various technologies such as generators, motors, transformers, and magnetic sensors. It is also the principle behind the function of devices like speakers and microphones.