Are My Faraday's Law Homework Solutions Correct?

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Discussion Overview

The discussion revolves around the correctness of solutions to homework problems related to Faraday's Law, specifically focusing on induced emf, current direction, and waveform characteristics. Participants seek verification and clarification on their interpretations and calculations.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • The original poster expresses uncertainty about the induced current waveform and its relationship to magnetic flux, questioning if the current should follow the flux waveform.
  • Concerns are raised about the correctness of the expression for Vemf(t) and the average power delivered to the load resistor.
  • One participant explains the implications of Lenz's law, detailing how the induced current opposes the change in magnetic flux and suggesting that the current direction may have been misrepresented in the original poster's diagrams.
  • Another participant reiterates the explanation of current direction changes as the magnet passes through the loop, indicating a potential misunderstanding in the original poster's approach.

Areas of Agreement / Disagreement

Participants generally express uncertainty regarding the correctness of the original poster's solutions, with multiple viewpoints on the direction of induced currents and the resulting waveforms. No consensus is reached on the accuracy of the homework solutions.

Contextual Notes

The discussion includes assumptions about the behavior of induced currents and the interpretation of Lenz's law, which may depend on specific definitions and visual representations that are not fully detailed in the posts.

jegues
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Homework Statement



See the figures attached for each of the individual problem statements.

Homework Equations





The Attempt at a Solution



I'll start by explaining my concerns for each problem,

P1) Did I plot the Iinduced waveform correctly? I'm having some trouble picturing what the waveform of the magnetic flux would be, it seems to me as the current would increase as the flux increases so it should follow from the current waveform somewhat, correct?

P2) Is my expression for Vemf(t) correct? Is the expression I wrote down for the average power delivered to the load resistor correct?

P3) Again, I'm not sure if I've done this problem correctly, can someone check my results?

Thanks again!
 

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The falling magnet means that the loop experiences a changing magnetic flux so an emf will be induced which will give rise to an induced current in the loop.
The induced emf (and current) will oppose the change producing it (Lenz's law) which means that as the N pole approaches the loop the current will be in a direction to create a N pole (that is a current direction opposite to the direction you have drawn)
As the N pole leaves the loop the induced emf and current will change direction to produce an S pole of the loop
As the S pole approaches the loop the induced current will again oppose the change which will produce a S pole again from the loop... same current direction.
As the S pole leaves the loop the induced emf and current will be in a direction to create a N pole from the loop.
I think the curve should be 2 'pulses' going +ve...-ve...-ve...+ve
 
technician said:
The falling magnet means that the loop experiences a changing magnetic flux so an emf will be induced which will give rise to an induced current in the loop.
The induced emf (and current) will oppose the change producing it (Lenz's law) which means that as the N pole approaches the loop the current will be in a direction to create a N pole (that is a current direction opposite to the direction you have drawn)
As the N pole leaves the loop the induced emf and current will change direction to produce an S pole of the loop
As the S pole approaches the loop the induced current will again oppose the change which will produce a S pole again from the loop... same current direction.
As the S pole leaves the loop the induced emf and current will be in a direction to create a N pole from the loop.
I think the curve should be 2 'pulses' going +ve...-ve...-ve...+ve

So basically I've mixed the direction of the currents up as the magnet passes through the loop?
 
Bump, still looking for verification on the other questions.
 

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