Lenz's Law Flow Chart
For determining the direction of an induced current in a conducting loop
Picture a conducting loop and a
magnetic field
No
Is the flux
changing?
Is there
currently a
flux
through
the loop?
Yes
No
Is the flux
increasing?
No
There is no induced current.
Yes
Yes
There is no induced current.
Increasing or
Decreasing?
Increasing
Does the loop
want an
increasing flux?
Yes
Never Happen...go back!
Decreasing
No
Yes
What does
the loop
want?
Does the loop
want an
decreasing flux?
Loop creates an induced
magnetic field through its
center in the OPPOSITE
direction as the external
magnetic field so as to
cancel the increase in the
external magnetic field.
Never Happen...go back!
No
What does
the loop
want?
Loop creates an induced
magnetic field through its
center in the SAME direction
as the external magnetic
field so as to replace the
loss of the external magnetic
field.
There is now a
magnetic field through
the center of the
conducting loop.
To decrease the flux to
its previous state.
So what
does the
loop do?
To increase the flux to
its previous state.
So what
does the
loop do?
The Right Hand Rule for a loop indicates
that when the thumb points in the direction
of the magnetic field the curl of the fingers
are in the direction of the induced current in
the loop.
There is now a
magnetic field through
the center of the
conducting loop.
The Right Hand Rule for a loop indicates
that when the thumb points in the direction
of the magnetic field the curl of the fingers
are in the direction of the induced current in
the loop.