THE ELECTRIC CHARGE OF A PARTICLE (LIKE A PARTICLE’S MASS) IT IS A PROPERTY OF MATTER

SOME PARTICLES HAVE AN ELECTRIC CHARGE, OTHERS DO NOT:

THE ELECTRON AND THE UP AND DOWN QUARKS ARE EXAMPLES OF PARTICLES THAT HAVE A CHARGE: SOME PARTICLES HAVE AN ELECTRIC CHARGE, OTHERS DO NOT: UP QUARK CHARGE = +⅔ ELECTRON CHARGE = -1 DOWN QUARK CHARGE = -⅓

SOME PARTICLES HAVE AN ELECTRIC CHARGE, OTHERS DO NOT: THE PHOTON AND THE NEUTRINO ARE EXAMPLES OF PARTICLES THAT DO NOT HAVE A CHARGE: PHOTON CHARGE = 0 NEUTRINO CHARGE = 0

THE PROTON HAS A NET CHARGE OF +1 DUE TO THE QUARKS THAT MAKE IT UP PROTON CHARGE = +1 ⅔⅔ ⅔⅔ ⅓⅓

THE NEUTRON HAS A NET CHARGE OF ZERO DUE TO THE QUARKS THAT MAKE IT UP NEUTRON CHARGE = 0 PROTON CHARGE = +1 ⅔⅔ ⅔⅔ ⅓⅓ ⅓⅓ ⅓⅓ ⅔⅔ THE PROTON HAS A NET CHARGE OF +1 DUE TO THE QUARKS THAT MAKE IT UP

YOU ARE PROBABLY ALREADY FAMILIAR WITH SOME OF THE BEHAVIOURS OF CHARGED PARTICLES

YOU ARE PROBABLY ALREADY FAMILIAR WITH SOME OF THE BEHAVIOURS OF CHARGED PARTICLES FOR EXAMPLE, YOU ARE PROBABLY AWARE THAT LIKE CHARGES for example, two negative charges

YOU ARE PROBABLY ALREADY FAMILIAR WITH SOME OF THE BEHAVIOURS OF CHARGED PARTICLES FOR EXAMPLE, YOU ARE PROBABLY AWARE THAT LIKE CHARGES for example, two negative charges − − − −

YOU ARE PROBABLY ALREADY FAMILIAR WITH SOME OF THE BEHAVIOURS OF CHARGED PARTICLES FOR EXAMPLE, YOU ARE PROBABLY AWARE THAT LIKE CHARGES for example, two negative charges − − − −

YOU ARE PROBABLY ALREADY FAMILIAR WITH SOME OF THE BEHAVIOURS OF CHARGED PARTICLES FOR EXAMPLE, YOU ARE PROBABLY AWARE THAT LIKE CHARGES for example, two negative charges − − − − will REPEL each other

YOU ARE PROBABLY ALREADY FAMILIAR WITH SOME OF THE BEHAVIOURS OF CHARGED PARTICLES AND THAT, OPPOSITE CHARGES − − + +

YOU ARE PROBABLY ALREADY FAMILIAR WITH SOME OF THE BEHAVIOURS OF CHARGED PARTICLES AND THAT, OPPOSITE CHARGES

YOU ARE PROBABLY ALREADY FAMILIAR WITH SOME OF THE BEHAVIOURS OF CHARGED PARTICLES AND THAT, OPPOSITE CHARGES will ATTRACT each other

A BEHAVIOUR OF CHARGED PARTICLES THAT YOU MAY NOT BE FAMILIAR WITH IS WHAT HAPPENS TO THEM IN A MAGNETIC FIELD * *The concept of FIELDS are useful in explaining so-called “action-at-a-distance” forces. For example, a gravitational field can be used to explain the attractive force of gravity, and an electric field can be used to explain the attraction of opposite charges and the repulsion of like charges. Likewise, magnetic fields can be used to explain why like poles of two magnets repel each other and their opposite poles attract.

You have probably seen how iron filings line themselves up around a bar magnet:

We say that the iron filings align themselves with the magnetic field that surrounds the magnet.

To show what happens to charged particles in a magnetic field, we take a “horseshoe” magnet…

S N To show what happens to charged particles in a magnetic field, we take a “horseshoe” magnet…

N S …and let this box outline the region where the magnetic field is concentrated.

N S The field has a direction associated with it, as shown by the arrow. The direction of a magnetic field always points from the North pole to the South pole of the magnet. Direction of magnetic field

N S If we were to send two charged particles of equal mass into the magnetic field… Direction of magnetic field

N S …one that is negatively charged…   Direction of magnetic field

N S …and one that is positively charged…   Direction of magnetic field

N S   …we would find that the negatively charged particle would be deflected in this direction… Direction of magnetic field

N S   …we would find that the negatively charged particle would be deflected in this direction…

N S Direction of magnetic field …and that the positively charged particle would be deflected by the same amount but in the opposite direction.  

N S …and that the positively charged particle would be deflected by the same amount but in the opposite direction. Direction of magnetic field  

N S …and that the positively charged particle would be deflected by the same amount but in the opposite direction. Direction of magnetic field (You should realize that using a magnet in this way could also be used to DETECT that two UNKNOWN particles had the SAME mass but OPPOSITE charge).  