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1. a coil is being rotated at a frequency of 50Hz in a magnetic field of field density B, what is the average emf induced and maximum emf induce? Area = a and number of turns = N.
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(Original post by Puddles the Monkey)
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3. (Original post by jonnypdot)
a coil is being rotated at a frequency of 50Hz in a magnetic field of field density B, what is the average emf induced and maximum emf induce? Area = a and number of turns = N.
What issues do you have with this problem?

Are you able to show me an attempt at the question?
4. (Original post by hezzlington)
What issues do you have with this problem?

Are you able to show me an attempt at the question?
i just thought of it because emf graphs are usually sine or cosine waves so how can i determine average emf.
5. (Original post by jonnypdot)
i just thought of it because emf graphs are usually sine or cosine waves so how can i determine average emf.
Well, what is the average for a periodic waveform? The positive values cancel out the negative values, giving you an average of zero.

Okay, for some reason latex is really messing up for me.

Maximum emf is w*BA*sinw*t

w = omega
6. (Original post by hezzlington)
Well, what is the average for a periodic waveform? The positive values cancel out the negative values, giving you an average of zero.

Okay, for some reason latex is really messing up for me.

Maximum emf is w*BA*sinw*t

w = omega
but i thought the current coming from mains supply is created from alternating pd
7. (Original post by jonnypdot)
but i thought the current coming from mains supply is created from alternating pd
The problem you're describing sounds very similar to an alternator (used in cars). The emf varies sinusoidally and you get an alternating current that also varies sinusoidally in magnitude and direction.
8. (Original post by hezzlington)
The problem you're describing sounds very similar to an alternator (used in cars). The emf varies sinusoidally and you get an alternating current that also varies sinusoidally in magnitude and direction.
so i was describing a different concept? If so lets forget about it. Also can i ask you a question regarding electric fields?
9. (Original post by jonnypdot)
so i was describing a different concept? If so lets forget about it. Also can i ask you a question regarding electric fields?
It sounds like you were possibly trying to describe a direct-current generator that produces emf of the same sign (e.g. no negative values). The DC generators used commercially have lots of coils and commutator segments which smooth out the bumps in emf so that your terminal voltage is one directional and pretty much constant.

For a problem involving a dc generator, you can calculage average back emf.

10. (Original post by hezzlington)
It sounds like you were trying to describe a direct-current generator that produces emf of the same sign (e.g. no negative values). The DC generators used commercially have lots of coils and commutator segments which smooth out the bumps in emf so that your terminal voltage is one directional and pretty much constant.

For a problem involving a dc generator, you can calculage average back emf.

so i have 2 positive charges if they are separated by a distance d what will the electric field strength at the mid point be? Would i just add the electric field strength for each charge at a distance d/2?

If i had unlike charges would i still have to add the electric field strength? a
if i had 2 negative charges i would have to find the net electric field strength right?
11. (Original post by jonnypdot)
so i have 2 positive charges if they are separated by a distance d what will the electric field strength at the mid point be? Would i just add the electric field strength for each charge at a distance d/2?

Yes. This is known as the superposition of Electric Fields and you use it a lot when dealing with distributions of point charges.

(Original post by jonnypdot)
If i had unlike charges would i still have to add the electric field strength? a
Two unlike charges is also known as an electric dipole.

Total field is denoted as a. So you need to calculate both the field strengths of each test charge, then add them together, yes.

(Original post by jonnypdot)
if i had 2 negative charges i would have to find the net electric field strength right?
Calculate the E of each, taking into account direction, and then add them. Same process.
12. (Original post by hezzlington)
Yes. This is known as the superposition of Electric Fields and you use it a lot when dealing with distributions of point charges.

Two unlike charges is also known as an electric dipole.

Total field is denoted as a. So you need to calculate both the field strengths of each test charge, then add them together, yes.

Calculate the E of each, taking into account direction, and then add them. Same process.
thank you so much for your help.
13. (Original post by jonnypdot)
thank you so much for your help.
No worries.

Need any more help then feel free to message me.

LaTeX is being fixed soon, so I'll be more helpful when that happens

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