Conceptual Questions Lenz's Law, Solenoid

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Homework Help Overview

The discussion revolves around conceptual questions related to Lenz's Law and the behavior of a solenoid with an internal wire loop when a voltage is applied. Participants are exploring the implications of changing magnetic fields and induced currents within the context of electromagnetic theory.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are attempting to apply Lenz's Law to determine the direction of induced currents and magnetic fields in response to changes in voltage. Questions are raised about the application of the right-hand rule and how the magnetic field inside the solenoid influences the current in the internal loop.

Discussion Status

Some participants are sharing their reasoning and interpretations regarding the direction of the magnetic field and induced current, while others are seeking clarification on the principles involved. There is an ongoing exploration of the concepts without a clear consensus yet.

Contextual Notes

Participants are working with the assumption that the magnetic field direction and induced current behavior are governed by Lenz's Law, but there is uncertainty regarding the specific outcomes of the scenarios presented in the homework questions.

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Homework Statement



https://www.dropbox.com/s/17hsoz0zdfoston/Screen shot 2013-05-10 at 12.37.44 PM.png

1) A voltage is applied to a solenoid such that a current is flowing in the indicated direction. Inside the solenoid is a single wire loop that is oriented in the same direction as the solenoid windings.

Which one of the following statements is true in the case where the voltage applied to the solenoid is increased?
a) The magnetic field of the solenoid points to the left while the induced current at location A points out of the paper.
b) The magnetic field of the solenoid points to the right while the induced current at location A points into the paper.
c) The magnetic field of the solenoid points to the left while the induced current at location A points into the paper.
d) The magnetic field of the solenoid points to the right while the induced current at location A points out of the paper.

2) Which one of the following statements is true in the case where the voltage applied to the solenoid is increased?
a) The magnetic dipole moment of the loop points to the right.
b) The torque on the loop points into the paper.
c) The torque on the loop points out of the paper.
d) The magnetic dipole moment of the loop points to the left.
e) A voltage is only induced in the inner loop, not in the solenoid itself.

Homework Equations



Lenz's law

The Attempt at a Solution



I thought the answer to question 1 was c) since the magnetic field would point in the opposite direction to fight the increase in magnetic flux, but it was wrong. I have no idea where to start for the second question. Thanks in advance!
 
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A to part 1, wrap your hand around the wire around the solonoid. Where do the fingers point?
 
To the right. I know how to use the right hand rule, but in this situation I am confused with the loop inside the solenoid. The magnetic field inside the solenoid points to the right, but how does that affects the current inside the loop? Would the current at location A point outside the paper?
 
What does Lenz law state? Something like the current would oppose the change in the field?
 

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