Calculating Induced EMF in a Coil with Uniform Magnetic Field

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To calculate the magnitude of the induced EMF in the copper wire, apply Faraday's Law, which states that EMF equals the rate of change of magnetic flux. In this scenario, the magnetic flux is constant, calculated as the product of the magnetic field strength and the area of the wire loop, while the number of turns (N) changes over time as the wire unrolls. The relationship between the unrolling speed and the number of turns can be established by considering how quickly the wire is being pulled off the roll. It's important to post homework questions in the appropriate forum to receive proper assistance. Understanding these principles is essential for solving the problem correctly.
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I have a homework problem where there is a long copper wire around a toilet paper roll that is placed in a uniform magnetic field. The axis of the roll is aligned with the field.
I am given the radius of the roll, strength of the field, and a velocity at which the wire is unrolled.
How do i calculate the magnitude of the EMF induced in the wire??
 
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How do you associate a speed to the unrolling?!? I don't understand.
Could you post the problem exactly as it it written please?

Btw - you posted in the wrong forum. Next time, please post in the appropriate sub-forum among those:

https://www.physicsforums.com/forumdisplay.php?f=152
 
Note that as it's said in Faraday's Law EMF is equal to d(N*magnetic_flux)/dt where N is a total amount of wire turns and magnetic_flux is per each one.

In your example your, magnetic_flux is const. and equal to BS=pi (r)^2 B. And only N changes in time. Try to think about dependence between N and time
 
What I have a lot of trouble understanding is... how do people with some sort of science education consistently misinterpret the sticky at the top of the forum that says 'Do not post your homework questions here.'? There are forums for that, but this is not one of them.
 
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