How Is Voltage Induced in a Rotating Coil Within a Magnetic Field?

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Homework Help Overview

The discussion revolves around the induction of voltage in a circular coil rotating within a magnetic field. The problem involves calculating induced peak voltage, sketching the time-dependence of the induced voltage, and determining the direction of rotation of the coil based on the magnetic field orientation.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the calculation of the area of the coil and the angular frequency based on the given frequency. There is an attempt to apply the formula for induced voltage and a question about the conditions for peak voltage. Some participants express confusion regarding the application of the right-hand rule and Lenz's Law for determining the direction of rotation.

Discussion Status

Some participants have provided calculations for parts A and B, expressing confidence in their results. However, there remains uncertainty about part C, with requests for clarification on how to apply the concepts involved. The discussion reflects a mix of attempts and questions, indicating ongoing exploration of the topic.

Contextual Notes

Participants note a lack of prior instruction on the relevant equations and concepts, which may be contributing to their confusion and requests for further explanation.

bpaterni
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Homework Statement



1.A circular coil, with radius of 10 cm, and 25 turns, rotates in a constant magnetic field of
strength 2.4 T, with the axis of rotation perpendicular to the direction of the magnetic
field.

A. If the coil rotates at a frequency of 50 Hz, what is the induced peak voltage?
B. Sketch the time-dependence of the induced voltage.
C. If the magnetic field that the coil is in points down the page, which direction does the coil rotate? Answer for both cases: (1) q traveling from left to right and (2) q traveling from right to left in the coil.

Homework Equations



V = -N * [ dΦ / dT ]
Φ = B * A * cosθ

V = -N * B * A * ω*sinθ
ω = 2π*f

The Attempt at a Solution



A. A = π*.1^2
.031416 m^2

ω = 2π*50
314.159 rad/s

peak voltage would occur when the coil is perpendicular to the magnetic field correct? So would I put π/2 in for sin(x) and get the following?
V = 25 * 2.4 * .031416 * 314.159*sin(π/2)
1.88496 * 314.159
592.177 V
B. If A is correct, then would the time-dependence of induced emf look like a sin wave?
C. I take it I'm supposed to use the right-hand-rule and Lenz's Law for this question, but I'm slightly confused as to how to go about doing so
 
Last edited:
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bump, I believe A and B are correct from what I understand, but I'm still having trouble with C.
 
I need help with this question too.
 
Yeah, I don't understand how to use the 50Hz to determine the peak voltage. I really hate this class! None of this was taught in the lesson or explained at any point. An explanation of the equations would be helpful. Please, anyone?
 

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