Transcript Magnetic Induction

• Magnetic Field
– Symbol: B
– Units: Who cares?
• Force
– Symbol: F
– Units: You’d better know this one!
• Velocity
– Symbol: v
• Current – interchangeable with velocity
– Symbol: I
– (as in “I don’t know why the symbol for
Current is I!”)
•Up
•Down
•Left
•Right
•Out (towards)
•In (away)
Right Hand Rule #1
• How do you tell if
the force is up or
down on the
Positive Charge?
• Use the Right
Hand Rule #1!
– v – thumb
– B – index finger
– F – middle finger
v
B
F
http://www.physics.brocku.ca/faculty/sternin/120/slides
Right Hand Rule #1
• A magnetic field
(B) will exert a
v
v
force on a charge
only if it is
F
F
moving
perpendicular to
the field
B • Funny- what
• As it turns out,
happens when
the direction of
Force is
the Force is
always
perpendicular to
perpendicular
to v ?
both B & v
Right Hand Rule #1
• If the charge is
negative, then just
use your left hand!
v
• Helpful Hint:
B
– Current is
considered the flow
of POSITIVE charge
F
http://www.physics.brocku.ca/faculty/sternin/120/slides
Right Hand Rule #2
• This is an easy
one!
• A Magnetic Field
wraps around a
current-carrying
wire
B
I
http://physics.pingry.org/Explorations/Magnetism/RightHand/Media/Solenoid.gif
Right Hand Rule #2
• What if the wire
is not straight,
but a loop?
I
• Thumb- B field
• Fingers- Current
B