Reality of Electric Field
The electric field has been introduced as a mathematical convenience, just as the gravitational field of Physics 111.
However, there is MUCH MORE to the electric field than this!
IMPORTANT FEATURE: E field propagates at speed of light.
- NO instantaneous action at a distance!! (we will explore this aspect in detail when we get to electromagnetic waves)
- i.e. as charge moves, resultant E field at time t depends on where charge was at time t-dt.
- We avoid these complications for now by restricting ourselves to situations in which the SOURCE of the E field is AT REST! (i.e. electrostatics)