Faraday's law and perpetual motion

  • Thread starter Thread starter Princess19
  • Start date Start date
  • Tags Tags
    Faraday's law Law
AI Thread Summary
A positive sign in Faraday's law would imply that the induced electromotive force (emf) reinforces the change in magnetic flux, potentially leading to perpetual motion. This scenario contradicts the law of conservation of energy, as it suggests a system that continuously accelerates without energy loss. Participants in the discussion agree that while it may not be technically classified as perpetual motion, the concept aligns with the idea of continuous movement. The consensus leans towards the answer being "true" in the context of the question posed. Overall, the discussion highlights the implications of altering Faraday's law and its effects on energy conservation.
Princess19
Messages
36
Reaction score
0
If a positive sign were present in Faraday's law instead of a negative sign, this would lead to perpetual motion..

True or false?
 
Physics news on Phys.org
Is this a homework question?
 
no, its a test question and i want to see if i got it right :)
 
perpetual motion of?
 
I think the answer is true, since the sign is positive, it doesn't oppose the change in magnetic flux, therefore violating the law of conservation of energy, and itll never stop moving as it increases in velocity.
 
Agreed. Consider a wire ring in a changing magnetic field. The induced emf would generate a current whose magnetic field reinforced (instead of opposed) the external field, creating positive feedback. I wouldn't call that perpetual motion exactly, but in spirit "True" is the right answer.
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Faraday's law help -- Induced EMF vs. time graph
Replies
7
Views
2K
Electromagnetic induction (Faraday's law)
Replies
7
Views
1K
Magnetic energy density, self-inductance of coaxial cylindrical shells
Replies
10
Views
1K
How to obtain correct negative sign in calculation of motional emf?
Replies
2
Views
894
Confusion about applying Faraday's law to a circuit
Replies
3
Views
845
Understanding the math of definition of electromotive force
Replies
1
Views
940
Making sense of sequence of ideas in MIT OCW's 8.02 notes on Faraday
Replies
1
Views
1K
Sign of the Faraday-Lenz equation
Replies
1
Views
1K
About changes in a magnetic field
Replies
1
Views
1K
Solving Faraday's Law: 0.73V Induced EMF Help Needed
Replies
9
Views
3K

Hot Threads

Recent Insights

Back
Top