Lesson 5 More Magnetism and Current Liceo Alfano

Reminder Force of a magnetic field on a moving charged particle: F = q v x B Right hand rule: Thumb in the direction particle is moving Other fingers in the direction of the magnetic field Force comes out of your palm

Reminder A wire with current creates a magnetic field around it Right hand rule: Thumb points in the direction of current Fingers curl in the direction of the magnetic field

Reminder Question I have a coil with current I and radius R, as shown. Which way is the magnetic field at point P? 1) Up 2) Down 3) Left 4) Right 5) Into the page 6) Out of the page

Reminder Question I have a coil with current I and radius R, as shown. Which way is the magnetic field at point P? 1) Up 2) Down 3) Left 4) Right 5) Into the page 6) Out of the page

Concept Question If I have two parallel wires with currents moving in the same direction, the wires will 1) Attract 2) Repel 3) Push in another direction 4) Nothing will happen

Concept Question If I have two parallel wires with currents moving in the same direction, the wires will 1) Attract 2) Repel 3) Push in another direction 4) Nothing will happen

Videos Parallel wires animation What do you think would happen if the currents went in different directions? Parallel wires in series animation Parallel wires video

Force on a Current Loop Let’s look at a loop of current in a magnetic field Which direction is the force on each part of the wire? What do the forces cause the loop to do?

Electric Motor This is how an electric motor works! Use a magnetic field to cause a wire to turn, which can be used to do work Electric motor experiments

Electromagnets We learned that a wire with current running through it creates what? Is this magnetic field strong enough to have a large effect? (think: do the wires in your house attract paper clips?) How can we make the magnetic field stronger? Loops! We can create an electomagnet by looping a wire with current around a conductor, i.e. a screw

Video Electromagnet experiment

Experiment Magnetic field induction experiment