Flux = 
= B•A = BA cos
Area vector = A is constructed normal to
surface with a length = to its area π r2
.
B
A
B
Flux = 
= B•A = BA cos
Area vector = A is constructed normal to
surface with a length = to its area π r2
.
B
A
B
Flux = 
= B•A = BA cos
Area vector = A is constructed normal to
surface with a length = to its area π r2
.
B
A
B
The AP B Ref Table writes
B
A loop of wire having an area of 0.25 m2 contains a magnetic
field intensity of 16 Teslas as shown. Find the magnetic flux
through the loop.
The AP B Ref Table writes
B
A loop of wire having an area of 0.25 m2 has 8 Webers of
magnetic flux passing through the loop. Find then strength of
the magnetic field inside the loop.
The E&M C Ref Tables write……..
B
A loop of wire having an area of 0.25 m2 has 8 Webers of
magnetic flux passing through the loop. Find then strength of
the magnetic field inside the loop.
The AP B Ref Table writes
And E&M C says….
b) tell which way current would flow
to resist the change.
c) What if there were 3 loops?
n
B
A loop of wire having an area of 0.25 m2 has 8 Webers of
magnetic flux passing through the loop. If the field collapsed in
4 seconds……..
a) find the EMF the loop would generate.
Two AP B formulas for induced E
EMF induced by the rate of change in
magnetic flux
EMF induced by the speed you move a
wire through a constant B field
Example problem: A 50 cm rod of resistance 2 ohms is moved across a
4 Tesla magnetic field at 2 m/s. Calculate…..
a)…the EMF generated.
b) …the current generated.
The direction of I is
defined by the cross
product E
=l
vxB
The B Ref Table says
• Force on a charge moving
through a B field (q v x B)
• Force on a wire carrying
current through a B field
The C Ref Table says
(i
l x B)
• Force on a charge moving
through a B field (q v x B)
• Force on a wire carrying
current through a B field
(l
i x B)
Find the direction and magnitude of the force
on a 20 cm wire that carries 3 Amperes across
a 4 Tesla field.
B Ref Table says
• As you get farther away from
the wire its field gets…..
weaker
Find the strength of a magnetic
field 2 mm away from a wire
carrying 10 amperes of current.
C Ref Table says
and call it Ampere’s
Law