Confirming Faraday's Law - interference in measurement.

Click For Summary

Homework Help Overview

The discussion revolves around an experiment aimed at confirming Faraday's Law, specifically the relationship between electromotive force (EMF) and the rate of change of magnetic flux. The original poster reports disturbances in the EMF measurements during the experiment, seeking insights into potential causes of this interference.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants inquire about the experimental setup, including the method of measuring EMF and the specifics of the motor and solenoid configuration. There are questions regarding the potential impact of the measuring device and the motor's operation on the observed noise.

Discussion Status

The discussion is ongoing, with participants providing suggestions for clarifying the experimental details. Some have proposed possible sources of interference, such as motor vibrations and connections within the setup, but no consensus has been reached on the exact causes.

Contextual Notes

There is uncertainty regarding the measurement device used, and the original poster expresses difficulty in providing additional details about the experiment. The discussion reflects a need for more information to better understand the sources of noise in the measurements.

peripatein
Messages
868
Reaction score
0
Hi,

Homework Statement


We ran an experiment for confirming the linearity of Faraday's Law (the relation between EMF and the rate of change of flux), by plugging a magnet to a motor rotating in the axis of a solenoid (inductor). In my graph of the amplitude of EMF wrt time, I noticed some disturbances on a few of the peaks. What might have been the causes of such interference("noise")?
I'd appreciate some insight, please.

Homework Equations





The Attempt at a Solution

 
Physics news on Phys.org
You might give some more details of your experiment. What do you mean by "plugging a magnet to a motor rotating in the axis of a solenoid (inductor)." Are you changing the speed of the motor or just plotting the emf vs time. How are you measuring the emf, a scope?
 
We were measuring the EMF produced as a result of the rotating magnet inside the solenoid, by changing the angular frequency of the rotation (the speed of the motor). Hence, for various frequencies we obtained various EMFs. I cannot tell for sure, I fear, whether the device used to measure the EMF was a scope.
Is it nevertheless clearer now? Could you assist?
 
I agree with barryj, you need to describe the setup in detail. For example, the solenoid has inductance and a 'scope has capacitance, which might result in peaking somewhere. Etc.
 
I am not really sure how to provide more details than I already have. We might have indeed used a scope, and it's highly likely we did, but I couldn't vouch for that. Anything else?
 
I am merely interested in the possible, most probable causes for the interferences ("noises") shown in the graphs, as a means of explaining them.
 
peripatein said:
I am merely interested in the possible, most probable causes for the interferences ("noises") shown in the graphs, as a means of explaining them.

So how about showing us the data? We can't perform an autopsy without a body ... :smile:
 
Please see attachment. Y axis is EMF, X axis is time. I hope this will suffice :)
 

Attachments

  • Untitled.jpg
    Untitled.jpg
    33.6 KB · Views: 375
As a guess, I'd suspect motor vibrations. The noise is not random, that's for sure. And the "plugging" of the magnet into the motor, that connection might have some slop in it.

About the best I can do I'm afraid.
 

Similar threads

Magnetic energy density, self-inductance of coaxial cylindrical shells
  • · Replies 10 ·
Replies
10
Views
2K
Lenz's Law and Faraday's Law clarification
  • · Replies 11 ·
Replies
11
Views
3K
Current in circular wire surrounding infinite solenoid in a circuit
  • · Replies 7 ·
Replies
7
Views
2K
Induced EMF in a circle: Faraday's law
  • · Replies 11 ·
Replies
11
Views
3K
Faraday's Law: Induced Voltage and Current in a Loop with Resistance R
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Motional EMF in Faraday disc, co-rotating magnet axial mean flux
  • · Replies 5 ·
Replies
5
Views
1K
EMF induced in a coil encircling an ideal solenoid
  • · Replies 2 ·
Replies
2
Views
2K
Calculating Induced EMF using Faraday's Law: A Magnetic Flux Problem Solved
  • · Replies 5 ·
Replies
5
Views
4K
What is the Correct Approach for Solving Faraday's Law Problem?
  • · Replies 5 ·
Replies
5
Views
2K
SAT II Physics -- Induced current in loop (Faraday's law)
  • · Replies 8 ·
Replies
8
Views
3K