Lenz's Law question (1 Viewer)

[lacklustre]

The following question came from Dot Point physics, but for the life of me I can't figure out how to do these types. If anyone can tell me the answers and their rationale it would be greatly appreciated.

 

[yorkstanham]

Ill just do part J you can just work the rest from there.

First point your fingers in the direction of the magnet field, which is into the page.

Point your palm in the opposite direction of the arrow, since a current is induced to oppose the motion, which is to the left

The current is flowing in the direction your thumb is pointing which is down the page

Therefore the current will clockwise.

I hope that is correct, if not im sorry

 

[lacklustre]

The current is flowing in the direction your thumb is pointing which is down the page

Therefore the current will clockwise.

I understand everything up to the part above. How do you conclude that the current is clockwise? (somehow i feel like I am missing something blatantly obvious)

Thank you so far (and yes I checked, your answer is correct =)

 

[undalay]

For the coils inside the magnetic field completely:
E.g. G, H.
Using ur hand rule.
For the top of the coil, of say...G the current is anti clockwise.
BUT if you use it again on the bottom of the boil, it's clockwise!.
They cancel eachother out, and thus no current.

Now for say I.
The current on both sides is upways.
So theres a current clockwise on the left side, and anticlockwise on the right side.
However the magnetic field lines are greater on the right side.
Thus the anticlockwise current overpowers the clockwise current, and such the current is anticlockwise.

 

[lacklustre]

Ah thanks, I think I kinda get the concept.

IMO Jacaranda Physics doesn't go into this in enough detail hence my confusion.

 

[namburger]

For the coils inside the magnetic field completely:
E.g. G, H.
Using ur hand rule.
For the top of the coil, of say...G the current is anti clockwise.
BUT if you use it again on the bottom of the boil, it's clockwise!.
They cancel eachother out, and thus no current.

You could just see that there is no change in magnetic flux, therefore no induced current

 

[undalay]

You could just see that there is no change in magnetic flux, therefore no induced current

Don't be tricked, this is not always the case.

 

[namburger]

Don't be tricked, this is not always the case.

Shit gimme example

 

[undalay]

try this

 

[namburger]

try this

Anticlockwise current?

 

[undalay]

i dunnno lool. i got clockwise.

 

[namburger]

Yeh its clockwise my bad, was using left hand.

I think you should just check in different parts of the conductor with your right hand to be sure =D
Thx jimmy

 

[Forbidden.]

try this

a.k.a. any change in motion of the conductor with respect to a magnetic field in a non-parallel direction leads to a change of position of magnetic field lines i.e. flux which then leads to induced current.

 

[barry1]

to Lacklustre:

I suggest you use the Surfing Physics book on motors and generators for more practice also for people like me who have their half yearlies in just over a week I STRONGLY suggest u buy/borrow The excel book "Revise HSC Physics in a month". All the main concepts are there all you have to do is memorize it

 

[lacklustre]

to Lacklustre:

I suggest you use the Surfing Physics book on motors and generators for more practice also for people like me who have their half yearlies in just over a week I STRONGLY suggest u buy/borrow The excel book "Revise HSC Physics in a month". All the main concepts are there all you have to do is memorize it

Haha same person who wrote Dot Point (Shadwick) also wrote Surfing physics.

I have the macquarie revision guide for physics. Is it about the same as those summary guides you mentioned?

 

[gorillaunsw]

try this

this one has a change in flux as flux is BA...and since the A is decreasing the flux is changing over time...hence there is an EMF...

when the area does not change and the coil is being moved through a constant magnetic field the flux in the coil does not change over time...

hence...if there is a coil that is not changing but moving through a magnetic field no induced current...

kind regards..