1. Electromagnetism Chapter 22

2. contents  Force on a current-carrying conductor  Force on beam of charged particles  Fleming’s Left-hand rule  Turning effect of a current-carrying coil in a magnetic field  The D.C. Motor  Chapter Review  Force on a current-carrying conductor  Force on beam of charged particles  Fleming’s Left-hand rule  Turning effect of a current-carrying coil in a magnetic field  The D.C. Motor  Chapter Review

3. Force on a current-carrying conductor Apparatus to demonstrates force on a current-current conductor in an external magnetic field

4. Force on a current-carrying conductor Before Switch ON After Switch ON

5. Force on a current-carrying conductor Before Switch ON After Switch ON

6. Force on a current-carrying conductor ▪ Current-carrying conductor placed in a magnetic field will experience a force (known as Lorentz force) (Note: Current is not parallel to magnetic field) F = BILsin θ F:Lorentz Force on current- carrying conductor B:Magnetic Field Stength I:Current in conductor L:Length of conductor Θ:Angle between B & I

7. Fleming’s Left-hand rule Action = Force B = Magnetic Field C = Current ▪ Fleming’s left-hand rule is used to find the directions of force, magnetic field and conventional current when any of the other two quantities are known

8. Force on a current-carrying conductor Example: Current OFF Current UP Current DOWN

9. Force on a current-carrying conductor Example:

10. Force on a current-carrying conductor

11. Application: Moving Coil loudspeaker

12. Force on beam of charged particles Positive Charged Particles

13. Force on beam of charged particles Negative Charged Particles V F

14. Force on beam of charged particles

16. Used in Cathode Ray tube for - TV screen - computer monitors - Oscilloscope to study waveforms

17. Force on beam of charged particles F = qvBsin θ F:Force on charged particls B:Magnetic Field Stength q:Charge of the particles (Charge of 1 proton = 1.6 x 10 -19 C) (Charge of 1 electron = -1.6 x 10 -19 C ) v:velocity of the charged particles Θ:Angle between B & charged particles

18. Turning Effect of a current-carrying coil in a magnetic field Carbon Brushes Commutator

19. Turning Effect of a current-carrying coil in a magnetic field Purpose of the commutator: To reverse the direction of the current in the loop whenever the commutator changes contact from one brush to the other This ensures that the loop will always be turning in one direction

20. Turning Effect of a current-carrying coil in a magnetic field

23. The current-carrying coil in a magnetic field on the whole experiences a turning effect Turning force (or turning effect) can be increased by either (or both): -increasing the number of turns on the coil -increasing the current in the coil -place a soft-iron core within the field Application: Electric Motors like electric fans, hair dryers

24. Turning Effect of a current-carrying coil in a magnetic field

28. Force between two parallel Current-Carrying Wires Unlike currents repel

29. Force between two parallel Current-Carrying Wires Like currents attract

30. A Cyclotron – Charged Particles Accelerator

31. A Cyclotron – Charged Particles Accelerator

32. A Cyclotron – Charged Particles Accelerator

33. A Cyclotron – Charged Particles Accelerator

34. A Cyclotron – Charged Particles Accelerator

35. A Cyclotron – Charged Particles Accelerator