Electric Fields Flashcards
Define Coulombs Law
The magnitude of the force between 2 point charges in a vacuum is directly proportional to the product of their charges and inversely proportional to the square of the distance between the charges
Charges of the same sign… Charges of opposite signs…
Same sign: Repel Opposite sign: Attract
Compare the magnitude of electrostatic forces vs gravitational forces between 2 subatomic particles
Electrostatic forces are magnitudes bigger As mass of subatomic particles is tiny compared to the charge they carry
Define a bodies Field Line
The path a free positive test charge would follow if placed near a body with a bigger charge
What is the electric field pattern for 2 oppositely charged point charges
What is the electric field pattern for a Positive point charge
What is the electric field pattern for a negative point charge
What is the electric field pattern for a charged plate and a point charge that have opposite charges
What is the electric field pattern for 2 oppositely charged parallel plates
Define Electric Field Strength
The force per unit charge experienced by an object in an electric field
How does Electric field strength vary in a uniform and radial field
Constant in a uniform field
Varies in a radial field
What is (4πΣ0)-1
8.99x109
Are these quantities scalar or vector
Electric Field Strength
Electric Potential
Electric Potential Energy
Electric Field Strength - Vector
Electric Potential - Vector
Electric Potential Energy - Scalar
What is the electric field pattern for a uniform field
What is the derivation for Work Done to move a charge between plates equation
Work Done = Qx(Change in V)
Work Done = Fxd
E=F÷Q, so F=EQ
E=(Change in V) ÷ d, so d=(Change in V) ÷ E
Work Done = EQ x (Change in V)/E, E’s cancel
Work Done = Qx(Change in V)
What happens if you fire a point charge at a right angle to a uniform field
Particle will accelerate towards the side with an opposite charge with a parabolic shape
Define Electric Potential
The work done per unit positive charge on a positive test charge when it is moved from infinity to that position
How does Electric Potential vary with distance from a positive point charge
For a positive point charge, the force is repulsive
So all values for V will be positive
As to get further from zero (closer to the point charge) more energy would be needed to move against the repulsive force that is getting stronger
How does Electric Potential vary with distance from a negative point charge
When the charge is negative, the force is attractive
So all values of V are negative just like in a gravitational field
As a positive charge can lose energy to move away from 0 (towards the negative charge)
What is the gradient of a V-r graph at a point
The electric field strength at that point
Define electric Potential Difference
The energy required to move a unit charge between 2 points
Define electric potential energy
The work done on a positive test charge when it is moved from infinity to that position
What is an equipotential surface
A surface that the electric potential is the same everywhere
No work is done to move along it
What is the area under an E-r graph
Electric potential difference
