Week 1 Introduction and Electrostatic Field Flashcards
Define the Triboelectric Effect
Rubbing or touching between two objects can transfer electrons from one to the other
Give four facts about charge
There are two types of charge
Charge is quantised in units of electron/proton charge
Charge is conserved
Charge is Lorentz invariant
State Coulombs Law
F = Qq/4πεr^2
What should you always look for in EM questions
Symmetry
What is the simple Electric Field equation
E = F/q
what are the four rules for the electrostatic field lines
Number of lines is arbitrary but density represents strength
Field lines either terminate at charge or extend to infinity
Field lines never cross
Direction of the force experienced depends on the direction of field lines
what does Earnshaw’s Theorem state
Impossible to construct an electrostatic field that will hold a charged particle in empty space
how do we find the charge distribution
integrate the charge density divided by r^2 over all points
