How Well Do You Understand Inductive Circuits and Magnetic Fields?

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Homework Help Overview

The discussion revolves around inductive circuits and magnetic fields, focusing on concepts such as current and voltage relationships, oscillation frequency in LC circuits, magnetic flux, and the effects of magnetic fields on charged particles.

Discussion Character

  • Conceptual clarification, Assumption checking, Exploratory

Approaches and Questions Raised

  • Participants discuss the relationship between current and voltage in inductive circuits, the effects of circuit parameters on oscillation frequency, and the implications of magnetic fields on moving charges. Questions arise regarding the induced current in a loop when a magnet approaches.

Discussion Status

Some participants express uncertainty about the induced current in a loop when a magnet is moved toward it, with references to Faraday's law prompting further exploration of the topic. There is an ongoing dialogue about the nature of magnetic fields and their effects on current direction.

Contextual Notes

Participants are working within the constraints of homework guidelines, which may limit the depth of exploration into the concepts discussed.

nautica
Could you check these answers.

thanks

1) In a purely inductive circut, the current lags voltage by?

1/4 cycle

2) Which has the greatest effect in decreasing oscillation frequency of an LC circuit? Using Instead:
a) L/2 and C/2
b) L/2 and 2C
c) 2L and C/2
d) 2L and 2C I picked d

4) A coil has a resistance of 60 ohms and an impedance of 100 ohms. its reactance in ohms is: 80 Ohms

5) At any point the magnetic field lines are in the direction of:
a) the magnetic force on a moving poistive charge
b) the magnetic force on a moving negative charge
c) the velocity of a moving positive charge
d) the velocity of a moving negative charge
e) None of the above - I picked e)

6) and electron is moving north in a region where the magnetic field is south. the magnetic force exerted on the electron is? Zero

8) You push a permanent magnet with its north pole away from you toward a loop of conducting wire in front of you. Before the north pole enters the loop the current in the loop is?? zero

9) The normal to a certain 1 meter squared area makes an angle of 60 with a uniform mag field. the mag flux through this area is the same as the flux through a second area that is perpendicular to the field if the second area is? .5 meters squared.

10) A magnetic field exerts a force on a charged particle:
a) always
b) never
c) if the particle is moving across the field lines (I picked c)
d) if the particle is moving with the field lines
e) if the particle is at rest
 
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Originally posted by nautica
Could you check these answers.
All look good except for #8.
8) You push a permanent magnet with its north pole away from you toward a loop of conducting wire in front of you. Before the north pole enters the loop the current in the loop is?? zero
No. Consider Faraday's law.
 


Originally posted by Doc Al
All look good except for #8.
No. Consider Faraday's law.


I thought it was zero before it entered and then it resisted the change??

Nautica
 


Originally posted by nautica
I thought it was zero before it entered and then it resisted the change??
No, the field extends beyond the pole of the magnet. As the field through the loop changes, a current is induced.
 
So the current would be clockwise?
 
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