How Well Do You Understand Inductive Circuits and Magnetic Fields?

  • Thread starter Thread starter nautica
  • Start date Start date
  • Tags Tags
    Review
AI Thread Summary
The discussion revolves around verifying answers related to inductive circuits and magnetic fields. The current in a purely inductive circuit lags voltage by 1/4 cycle. Participants debated the effects on oscillation frequency in LC circuits, with one selecting option d) 2L and 2C. A key point of contention was the current in a loop of wire when a magnet's north pole approaches; it was clarified that the current is not zero due to Faraday's law, which states that a changing magnetic field induces current. The conversation emphasizes the importance of understanding magnetic field interactions and induced currents in circuits.
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
 
Physics news on Phys.org
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?
 
Last edited by a moderator:
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Back
Top