Electric fields Flashcards
Electric field def
Force per unit positive charge
Uniform electric field def
Where the electric field strength is the same at all points in the field
Electric field strength of uniform electric field formula:
E= ΔV/ Δd
What three factors are the motion of a charged particle in a uniform electric field influenced by?
- Mass ∝ Deflection
- Charge ∝ Magnitude of deflection
- Speed ∝ 1/ deflection
What is coulumb’s law
electrostatic force between two point charges is
directly proportional to the product of the two charges and
inversely proportional to the square of seperation
Electrostatic force formula
F=qE
Electric field per point charge formula
E= kQ/r²
Electric potential definition
Work done per unit positive charge in bringing a small test charge from infinity to that point
Electric field strength definition
The electrostatic force at a point per unit positve charge at that point
When is electric potential positive
when near an isolated positive charge
when is electric potential negative
when near an isolated negative charge
when is electric potential zero
at infinity
Equipotential line
A line joining all points with equal potential
When equipotential lines are equally spaced and parallel, what does it represent?
a uniform electric field
Explain why, for any point outside a spherical conductor, the charge on the sphere may be considered to act as a point charge at its centre. (2)
- electric field lines are radial/ normal to the surface of the sphere
- electric field lines appear to originate from the centre of the sphere
