Induced Current

  • Thread starter danago
  • Start date
  • #1
danago
Gold Member
1,122
4
On a particular dynamo, the rotating coil has 500 loops, each of area 2.5x10-4 m2. The magnetic field can assumed to uniform and of magnitude 0.400T. When the bicycle is ridden at a particular speed, the coil rotates with a frequency of 8Hz. What is the maximum emf produced? What is the average emf produced?

Ok. According to lenz's law, the emf is equal to the time rate of change of magnetic flux.

[tex]
\left| \varepsilon \right| = \frac{{d\Phi }}{{dt}} = \frac{d}{{dt}}(NAB\sin \theta ) = \frac{{d\theta }}{{dt}}NAB\cos \theta
[/tex]

I am told that it rotates 8 times per second, which is means that the angular frequency is given by:

[tex]
\frac{{d\theta }}{{dt}} = 16\pi
[/tex]

Therefore, the EMF is given by:
[tex]
\left| \varepsilon \right| = 0.8\pi \cos \theta
[/tex]

The maximum value of [tex]cos\theta[/tex] is 1, therefore the maximum EMF is ~2.51V. Is that correct? Also, how should i go about finding the average? Just divide it by [tex]\sqrt{2}[/tex]?

Thanks in advance,
Dan.
 
Last edited:

Answers and Replies

  • #2
learningphysics
Homework Helper
4,099
6
Looks right to me. yup divide the peak by sqrt(2).
 
  • #3
danago
Gold Member
1,122
4
Ah alright. Thanks for the quick reply :smile:
 

Related Threads on Induced Current

  • Last Post
Replies
5
Views
3K
  • Last Post
Replies
9
Views
2K
  • Last Post
Replies
2
Views
3K
  • Last Post
Replies
5
Views
3K
  • Last Post
Replies
3
Views
929
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
7
Views
7K
  • Last Post
Replies
3
Views
852
  • Last Post
Replies
6
Views
7K
  • Last Post
Replies
1
Views
1K
Top