General questions on A2 Electric and Magnetic Fields
What is Coulombs Law?
The force between two point charges (Q1 & Q2 ) placed r meters apart in a vacuum is given by
Electric Field Lines
These show the 'direction in which a free positive charge will move'.
The electric field lines between two parallel charged plates are parallel and run +ve to -ve
The electric field lines from a positive point charge lie in a 'star' pattern (pointing outwards)
Radial Electric Field
the electric field created by a pont charge are referred to as 'radial' and are also 'inverse square'. The E-field strength decreases as 1/distance2 . (So doubling the distance will QUARTER the field-strength.)
Uniform electric field
This occurs between two charged parallel plates. The E-field strength has the same value everywhere and is given by (V=Pd across plates and d= separation of the two plates.)
State the definition for capacitance
This is the charge required to raise the voltage across the capacitor by one volt. C=Q/V. Where Q=charge and V= potential difference. Unit: Farad (or Coulomb per volt)