Electric Fields
Define an 'Electric Field'
A region of space where a charged particle experiences a force
What is meant by a 'Uniform Electric Field'
An electric field with field lines that are equally spaced & parallel. The field strength is constant is constant all round
What is meant by 'Radial' fields
Where field lines are equally spaced as they exit a point of charge but the distance between them increases the further the field lines travel out.
What happens to the magnitude of force and the and the electric field strength as the field lines go further from the point of charge
They both decrease
For both positive and negative radial electric fields, which way do field lines act
Positive - they go outwards (from the point of charge)
Negative - they go inwards (from the point of charge)
Define 'Electric field Strength'
The force experienced per unit positive charge. The charge refers to the charge of the particle in the field, not the particle emitting the field.
Give the formula for 'Electric Field Strength' in a non-uniform field
Force/Charge
Give the formula for 'Electric Field Strength' in a uniform field
Voltage/distance (separation between the plates)
State Coulombs law
The electrostatic force between two point charges is proportional to the product of the charges and inversely proportional to the square of their separation
Give the formula for Electrostatic force
F = Qq/4πε0r²
What is the difference between attractive and repulsive forces.
Attractive forces are negative
Repulsive forces are positive
What does the electrostatic force equation show to us
That Electric field strength in a radial field is not constant
Give 3 differences between Gravitational and Electrical fields
- Gravitational arise from masses, electrical arise from charges
- Uniform g fields have parallel gravitational lines, electric fields have electric field lines
- Gravitational fields only attract, electrical both attract an repel
Define 'Electric potential'
The work done per unit charge to bring a positive charge from infinity, to that point
Give the formula for 'electric potential energy'
E = Qq/4πε0r
Give the formula for electric potential
V = Q/4πε0r
Give the formuls for the capacitace of a sphere
C = 4πε0r
State another formula for the electric field strength around a point charge
E = Q/4πε0r²