1 / 17

Magnetism

Magnetism. Magnetic Fields. Magnetism is also a field force. The field lines come out of North and go into South. In magnetism, opposites attract and like repel. Drawing Magnetic Field Lines (time for a demo! ). Time for a video from the “funny man”.

jeneil
Download Presentation

Magnetism

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Magnetism

  2. Magnetic Fields Magnetism is also a field force. The field lines come out of North and go into South. In magnetism, opposites attract and like repel. Drawing Magnetic Field Lines (time for a demo! )

  3. Time for a video from the “funny man” Current carrying wires will have a magnetic field around them in concentric circles. You can determine the direction of the circles using your right hand. Your thumb goes in the direction of the current and your fingers point in the direction of the field.

  4. Forces on charged particle in a magnetic field. Moving charges also have a magnetic field. As a result they experience a force when they move through a magnetic field. F = qvB F: Force (N) q: the charge (C) v: velocity of the moving charge B: Magnetic field strength (T, Teslas)

  5. Example #1 A proton moving east experiences a force of 8.8 x 10-19N upward due to the Earth’s magnetic field. At this location, the field has a magnitude of 5.5 x 10-5T to the north. Find the speed of the particle.

  6. You can find the direction of the force You use your right hand if it is a proton, left it is it an electron. Your fingers line up with the magnetic field. Your thumb points in the direction the charge is moving. Your palm shows the direction of the force on the charge. (Don’t worry, we will do some examples so you will understand)

  7. Example #2 A proton moves through a 5T magnetic field with a velocity of 4 x 105m/s. The field points in the positive x direction. The particle is moving in the positive y direction. What is the magnitude and direction of the force on the proton?

  8. Radius of the circle the charged particles make in a magnetic field. r: radius of the circle (m) m: mass of the particle v: velocity of the particle q: charge of the particle B: magnetic field strength

  9. Example #3 A proton is accelerated through a potential difference of 750V. It enters a 5T magnetic field directed out of the page. The proton is moving in the +x direction. A. Sketch the path of the proton. B. What is the proton’s velocity? C. What is the radius of its path? D. What electric field could be used to make the proton move in a straight line? E. Sketch the electric field.

  10. Current carrying wires are a lot of moving charges You can find the force on a current carrying wire in a magnetic field with the formula F = BIl B: magnetic field strength (T) I: current moving through the wire (A) l: length of the wire (m) Time for the funny man again! 

  11. You can predict the direction of the force on the wire too. For wires you always use your right hand. Fingers still point with the magnetic field. Your palm is still the force direction. Your thumb is the direction of the current.

  12. Example #4 A 2m section of wire is placed in a 3T magnetic field pointing west. The wire has a 3A current moving through it to the south. What are the magnitude and direction of the force on the wire?

  13. Example #5 A 50cm length of wire has 3A running through it. It experiences a force to the right when it is placed in a 4T magnetic field directed into the page. A. What is the magnitude of the force on the wire? B. Which direction is the current running?

  14. Two current carrying wires Two current carrying wires lying near each other will experience a force due to the magnetic field they induce. F: force (N) d: distance between wires(m) k’: 1 x 10-7 N/A2 I: Current in wires (A) l: length of the wire

  15. Example #6 Two 75cm long straight wires carry currents in the same direction. One has 2A and the other has 3.2A. They are lying 1.25cm apart. What is the force between the two wires? Current moving the same way, attractive force. Current moving opposite way, repulsive force.

  16. Magnetic field from two wires Calculate the magnetic field at the location specified for each wire. Current flowing the same direction, take the difference. Opposite directions, add.

  17. Example #7 Two wires are separated by 22cm and carry currents in opposite directions. The 1.5A wire flows east. The 4.5A wire flows west. Find the magnitude of the magnetic field halfway between the two wires?

More Related