U2.1 Forces on charged particles Flashcards
What happens to charged particles in an electric field?
They experience a force.
Where do electric fields exist?
Around charged particles and between charged parallel plates.
What is an electric field?
A region where an electrically charged particle experiences a force.
What way are field lines always drawn?
With an arrow pointing from positive to negative.
What happens when a charged particle/ charged object experiences an unbalanced force?
It will be accelerated.
What does the spacing between field lines indicate?
The strength of the force. If the lines are close together the force will be greater, eg close to a charged particle in a radial field.
What does parallel field lines indicate?
A uniform field. Indicates that the force is equal at all points in the field.
What happens if two objects of the same charge are brought together?
The force produced will be repulsive, they will be pushed apart.
What happens if two objects of different charge are brought together?
The force produced will be attractive, they will be pulled towards each other.
Define potential difference (voltage) in terms of work done and charge.
Work done per unit charge
How do you calculate the electric field strength?
The force, F per unit charge, Q.
Give 2 applications of electric fields.
Cathode ray tubes (CRT), the inkjet printer.
Describe how the cathode ray tube works.
It contains one or more electron guns used to accelerate the electrons to a high speed towards a fluorescent screen. Electrons from the cathode at the back of the tube are accelerated towards the anode by a high voltage, and are then deflected towards the correct part of the fluorescent screen by electric and magnetic fields.
What are cathode ray tubes used in?
TV’s, computer monitors, plasma and LCD screens.
Describe how an inkjet printer works.
Sprays tiny droplets of ink at the page from a print head, which is moved side-to-side as the paper moves through. The ink droplets have to hit the paper in a very precise place to accurately represent what is being printed.
