Electric And Magentic Fields Flashcards
What are the values represented by Q & q?
Q is the electric charge, in coulombs C, either positive or negative
q is the particle charge (e.g 1.6x10^-19 for an electron) can be positive or negative, in coulombs C
What happens if a charged object is placed in an electric field?
The object will experience a force
If the charged object is a uniformly charged sphere, where is the charge assumed to be concentrated?
In the centre of the sphere
What does the centre of a charged sphere act as? (Given this is where the charge is concentrated)
Acts as a point charge (producing a radial field)
How do you represent electric fields?
Field lines
What are the conditions for Coulomb’s law?
There have to be 2 point charges in a vacuum
Equation for Coulomb’s law?
F= Q1Q2/ 4 x pi x epsilon nought(the permittivity of free space= 8.85x10^-12F/m) x r^2
If the charges are opposite, meaning an attractive force, will the force be value be positive or negative?
Negative as the radius will be decreasing as the charges get closer together(via the attraction)
If Q1 and Q2 are of like charges e.g both positive or negative, meaning the force is repulsive, will the force value be positive or negative?
The force will be positive as the r value increases due to repulsion between the charges
Why (in terms of Coulomb’s law) does the force between charges become weaker with separation distance?
Because Coulomb’s law is an inverse square law
Which equation shows the inverse square law of Coulomb’s law?
F (direct proportionality symbol) 1/r^2
Define electric field strength
The force per unit charge
Show the equation linking the electric field strength, force and charge
E=F/Q
Is the electric field strength a scalar or vector quantity?
Vector, as it has a quantity but also direction of motion that the charge would move in
How does the location of the charge (q not Q) affect the field strength experiences by an object in either a radial or uniform field?
Stronger field strength closer to the centre of charge (Q) compared to further away. (Coulombs inverse square law)
Field strength is equal throughout a uniform electric field
What type of field does a point charge & ‘ any body that behaves as if it has all its charge concentrated at its centre’ generate?
Radial
In a radial field the electric field strength (E) depends on the distance (r) from what?
The point charge (Q)
State the equation for the electric field strength of a radial field
E=Q/4 x Pi x permittivity of free space(8.85x10^-12) x r^2
State the inverse square law of electric field strength & distance for a radial field
E (direct proportionality symbol) 1/r^2
What happens to the field strength of a radial field as you move further away?
It decreases as you move further away from Q (on the diagram the field lines separation increases )
How can you produce a uniform field?
By connecting two parallel plates to the opposite poles of a battery
How are the field lines represented in a uniform field?
They’re parallel and equidistant apart
Is a uniform field equal or not throughout?
Equal throughout (uniform and equidistant field lines)
What does the field strength between two plates depend on?
The potential difference between the plates
The separation distance between the plates
