direction of current flow in a generator (1 Viewer)

[vds700]

If you have a magnetic field running fom right to left and a coil in between, if the coil is spun clockwise through the field, which direction will the current flow?

`The text says you apply Lenz's Law so that a current is induced that opposes the original change in flux. It says a megnetic field will be induced to the left to oppose the external change in magnetic flux through the coil. You use the right hand grip rule for coils and the current will be clockwise (thumb pointing to the left). I kinda get that. They say the current emerges out from termnal B, therefore terminal B is positive. But doesn't conventinal; current frow from positive to negative terminal???


Any explanations would be greatly appreciated.

This is from Jacaranda Physics pg 140

 

[namburger]

i dont get it
If you say that the current emerges out from terminal B and it is positive, and that current goes from positive terminal to negative terminal, isn't it the same thing

 

[jcurry]

i dont get it
If you say that the current emerges out from terminal B and it is positive, and that current goes from positive terminal to negative terminal, isn't it the same thing

that is the same thing maybe he wrote it wrong
what is he asking exactly??

 

[benji6667]

i saw this same question in the jacaranda textbook.. and my physics teacher couldn't explain it,

i forgot how i work it out but the answer is correct

ill post back when i remember

 

[undalay]

you think u could scan it ?

I'm at page 140 but i dont see anything, maybe a different edition.

 

[vds700]

i dont get it
If you say that the current emerges out from terminal B and it is positive, and that current goes from positive terminal to negative terminal, isn't it the same thing

yeah if current goes from positive to negative, shouldn't it emerge from the negative terminal, ie terminal B is negative.

 

[vds700]

you think u could scan it ?

I'm at page 140 but i dont see anything, maybe a different edition.

I get how you use the right hand grip rule for coils, thumb pointing to the left so the current flows clockwise, im just confused about the polarity of terminals A and B

 

[undalay]

You know the rule (there are many) for determining the emf of a wire as it is moved?

Just use that one, on the right side of the coil.

(velocity downwards, magfield to the right)

and you'll see that induced current is moving from N to M, which is connected to terminal B, thus terminal B is positive.

 

[vds700]

Ah I get it now. Thanks!

Did you mean the left-hand rule? Fingers pointing in the direction of magnetic field, palm in the direction of the force applied and thumb points in the direction of induced current.

 

[m00]

anti clockwise =D

 

[fwong]

Hint: Think about the flow of (positive) current in a circuit driven by a battery. Outside the battery, current flows from + terminal to negative terminal, as we were taught. But look at what happens inside the battery, (positive) current flows from - to + terminal. Got it?

Teacher

 

[AnneZ]

I get how you use the right hand grip rule for coils, thumb pointing to the left so the current flows clockwise, im just confused about the polarity of terminals A and B

Sorry but i am so confused oabout the right hand grip rule, why the induced current is clockwise and how it indicates the current emerges from B???????I have been looking at the page for four hous but this parts is the part that i can never understand