Forces on Charged Particles

What force does this positive test have?

Outwards

What force does thisn positive test have?

Inwards

What happens to the strength of the fields as we move away from the charge?

Decreases

What do charged particles experience in an electric field?

A force

How can we tell the strength of the force in an electric field?

How close the field lines

Name 3 examples of everyday applications with electric fields?

Photocopying, pollution control, and paint spraying

Where do electric fields exist?

Around charged particles and between charged parallel plates.

What is voltage (potential difference) in terms of work done and charge?

For every 1J of work done in moving 1C of charge between 2 points, the potential difference is 1V

What does a moving charge produce?

Magnetic field

What will the energy appear as, if the charge moves in the direction of the electric force?

Kinetic energy

What will the energy appear as, if a positive charge is moved against the direction of the electric force?

Electric potential energy

What happens when a positive charge is released from a plate?

The electric potential energy converts into kinetic energy

What affects the direction of the magnetic field?

The direction of current flow

What does this **dot** represent?

Current coming **out** of the page

What does this **cross** represent?

Current going into the page

What are particle accelerators designed to do?

Speed up and increase energy of a beam of particles by producing electric fields that accelerate the particles.

What do beams of charged particles experience?

A deflection by both electric and magnetic fields

Where does the repelling of elecrtons from the negative electrode occur?

The cathode

Where does the attractions of elecrtons towards the positive electrode occur?

The anode

Why is the voltage across electrodes usually a few thousand volts?

So it gives the electron enough energy to make a small glow on the fluorescent screen

How do electrons keep moving in a linear accelerator?

They must always move from a negative electrode to a positive electrode

What do the series of elecrtodes do in an linear accelerator?

They keep electrons moving rather than using large voltages

What are the 3 types of particle accelerators?

Linear accelerator, Cyclotron and Synchrotron

Why are alternating supplies sometimes used in a linear accelerator?

So particle always accelerates in the same direction