Electric Fields Flashcards
What’s an electric field?
Region or space where an object experiences a non-contact force due to being charged
Electric field strength?
The force done per unit of charge
E = F/Q
What’s an equipotential?
A line of constant electric potential.
What’s the relationship between equipotential and radius (distance)?
The further away the field strength decreases.
What’s the formula for the field strength between 2 parallel plates?
E = V /d
E is field strength
V is p.d
d distance
What’s coulomb’s law?
It gives the attractive or repulse force between 2 point charges in a vacuum.
Coulomb’s law formula?
F = Q(1)*Q(2) / 4πε(0)r²
So F ∝ 1/ r²
ε(0) value
8.85x10-¹²
What’s the relationship between Q(1) and Q(2)
Always equal and opposite depending on the charge
Point charge?
Charge being concentrated at 1 point and has a radial field
Electric Potential?
The potential energy that a unit of charge (+1C) would have at a point
Electric Potential formula?
V = Q/4πε⁰r
Capacitors?
Electrical component that stores charge
What are capacitors made of?
2 conductive plates separated by air or an insulator
How do capacitors work?
When connected to a power source, a negative and positive charge is stored on each side and stopped by the insulator.
This causes a p.d leading to uniform electric field.
Capacitance formula?
C = Q/V
Formula for energy stored in a capacitor?
W = QV/2
W=CV²/2
W=Q²/2C
What effects the time taken to charge?
Capacitance and the resistance
In what way do capacitors discharge?
Exponentially
Q= Q(0)e^(-t/RC)
Or
Q = Q(0)e^(-t/τ)
What is the time constant (τ)
Time taken for 1/e of Q to discharge
τ=RC
What is an exponential curve?
A constant fractional change in a given time interval
What’s a uniform electric field and how can it be produced?
Parallel electric field lines that are always the same distance apart.
Produced when you put two parallel plates on the opposite poles of a battery
How are lines of equipotential shown from a point charge?
Circles with increasing distance away from the point charge
What is equipotential for a radial field?
Shows the points that are equally distanced apart.
