- #1

LCSphysicist

- 646

- 162

- Homework Statement
- ..

- Relevant Equations
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I need to find the FEM induced in a coil that rotates around the y-axis and is inside a solenoid. The coil starts in the plane yz

##r## is the radius of the coil

##n## is the number of spiral by length of the solenoid.

##N## is the number of turns of the coil

##w## is the angular velocity that the coils rotate.

##I## is the current passing through the solenoid

I just thought this:

$$\phi = \langle B,A \rangle = \mu n I \pi r^2 N cos(\theta = wt)$$

$$ \epsilon = -\dot \phi = \mu n I \pi r^2 N w sin(\theta = wt)$$

This is a simple exercise. But i can't see why my answer is wrong. That is, the answer provided by the list is ## \mu n I \pi r^2 N w cos(\theta = wt)##. The trignometric function is different. My answer says that at t=0 the induced FEM is zero, the other says it is maximum.

##r## is the radius of the coil

##n## is the number of spiral by length of the solenoid.

##N## is the number of turns of the coil

##w## is the angular velocity that the coils rotate.

##I## is the current passing through the solenoid

I just thought this:

$$\phi = \langle B,A \rangle = \mu n I \pi r^2 N cos(\theta = wt)$$

$$ \epsilon = -\dot \phi = \mu n I \pi r^2 N w sin(\theta = wt)$$

This is a simple exercise. But i can't see why my answer is wrong. That is, the answer provided by the list is ## \mu n I \pi r^2 N w cos(\theta = wt)##. The trignometric function is different. My answer says that at t=0 the induced FEM is zero, the other says it is maximum.