3.1 - Fields Flashcards
what is meant by an electric field
the region that surrounds electrically charged particles in which a force is exerted on other electrically charged particles
define electric field strength
the electrical force acting on
unit positive charge
what does an electric field line show
the direction a positively charged particle would move
define electrical potential at a point
the work done in moving a unit positive charge from infinity to that point
an electric field is a conservative field, what does this mean?
the energy required to move a charge between 2 points in an electric field is independent of the path taken
what did millikan’s oil drop experiment prove?
that electrons had a charge of (see data book)
describe millikans experimental method
oil drops are given a negative charge from electrons emitted by ionised air. Two charged plates balance a negatively charged oil drop causing it to float.
what values are needed to calculate the charge of an oildrop in millikans experiment
mass of drop, g, distance between plates, voltage between plates
what is an electronvolt (eV)
the energy acquired when an electron accelerates through a potential difference of 1 volt
convert 4 eV to joules
6.40871x10-19J
what do electrons individually produce
a magnetic effect
what are electrons around atomic nuclei
they are in motion
which metals can exhibit ferromagnetism
iron, nickel, cobalt and some rare earth metals
what is ferromagnetism
an effect in which magnetic dipoles can be made to align, resulting in the material becoming magnetised.
which fields have a weak strength
gravitational
