N/A - Electric fields Flashcards
What things have electric fields?
what is the unit of measurement?
what does a charged object experience when it is placed in a electric field?
Any object with charge has an electric field around it. Its measured in coulombs.
A force
What does e little 0 stand for?
what does q1 and q2 stand for?
What does r stand for?
- In the force between two point charges equation
“epsilon-nought”, the permittivity of free space
The charges of the two objects
distance between q1 and q2
What’s the relationship between the forces in the instance of two point charges that are attractive or repulsive? what direction is what charge?
The force on q1 is always equal and opposite to the force on q2, the direction depends on the charges.
If the charges are alike then the force is repulsive so F is positive. Other way round it is negative.
What law applies to coulomb’s law? explain it.
what else affects the size of the force F between two point charges when not in a vacuum?
What do you do if the question asks about air?
The inverse square law, so the further apart the charges, the weaker the force between them.
Also depends on permittivity of the material between them, Epsilon. if its air use epsilon naught tho
What is electric field strength defined as?
What does E stand for in the equation?
What are the units for electric field strength?
Electric field strength is defined as force per positive unit charge. The force that +1C would experience if placed in an electric field.
Electric field strength.
NC^-1
What are electric field lines? explain types of point charges and what they have.
Electric felid lines show the direction of the force that would act on a positive charge. A point charge has a radial field.
For a positive charge, electric field lines point away from the centre. For a negative charge they point towards the centre
What is the inverse square law?
As you get further away from the middle, the field strength decrease in portion to radius squared.
What is the Electric field strength in a uniform field?
Electric field strength in a uniform field is constant no matter where you are. Found in parallel plates
What is the acceleration and motion like on a charged particle in a uniform field? what about for positive and negative charges?
A charged particle that enters right angle to the electric field feels a constant parallel force to the electric field lines. If it is positively charged than it acts in the same direction and accelerates. If it is negatively charged it acts in the opposite direction to the field lines.
What is Electric potential? what does the size of the potential depend on?
All points in an electric field have an absolute electric potential, V. This is the EPE that a unit positive charge (+1C) would have at that point.
Distance from the charge creating the electric field and the size of that charge.
How does the size of V, (absolute electric potential) vary? positive, negative?
The size of V is greatest on the surface of the charge and 0 at infinity distance. as it decrease the further away you go. This is for a repulsive force so when q and the charge is positive.
Opposite for attractive, so when there is an attractive force.
What is electric potential difference? how do you find this on a graph of E(field strength) and r(radial distance) ?
if two points have a different absolute electric potential, then there is a electric potential difference between them. This is the energy needed to move a unit charge between those points.
Area between the two points
What does the size of the work done needed to move between two points in a radial electric field depend on?
depends on the size of the charge your moving and the size of the potential difference you want to move it across.
What’s an equipotential line in relation to electric fields?
Are lines where an electric charge can follow and there be no work done across it.
