Electric Fields Flashcards
What happens when 2 like charges are near each other ?
Repel each other
What happens when 2 opposite charges are near each other ?
Attract to each other
What happens when 2 charges are put further apart ?
The force between them will decrease
What is the unit for charge ?
Coulombs ( C )
What does it mean when the Force between 2 charges is positive/negative ?
Depending on charges
2 pos/neg -> positive force, repel
1 pos + 1 neg -> negative force, attract
What is the definition for Electric field ?
Force per unit positive charge on a small test mass
What does a uniform electric field look like ?
Straight lines from pos to neg
e- going to pos
p going to neg
In E = V / d
what is d
The distance between charged plates
How to calculate electric field at a point ?
Find the electric charge at that point
or others and then solve via cosine rule or pythagoras
What is the definition for electric potential ?
Work done per unit positive charge when moving a small positive test charge from infinity to the point
What is the unit for Electric Field ?
( E = F / Q )
Vm^-1
NC^-1
How to sketch the field lines for an electric field ?
Lines positive to negative
More field lines with greater magnitude
What does the graph for V against r look like ?
( V = 1/4πεo Q/r )
Y = 1 / x
- gradient is E against r
What does the graph of electric field against r look like ?
y = 1 / x
- gradient of potential against r
- area = potential against r
What is the graph of uniform potential against d look like ?
y = x
area of E = d
gradient is E against d
