paper 2 definitions Flashcards
(20 cards)
capacitance
charge stored per unit voltage by a capacitor
radioactive decay
isotopes have a random probability of decay
decay occurs randomly
activity
the number of nuclei that decay per second
half life
the average time taken for half of the unstable nuclei to decay
binding energy
the amount of energy required to separate a nucleus into its constituent nucleons
mass difference
the mass which corresponds to the binding energy of the nucleus
fusion
2 nuclei join together to form a larger nucleus
fission
nucleus splits to produce 2 smaller nuclei
critical mass
minimum mass of nuclear fuel required for a chain reaction to occur at at constant rate
absolute electric potential
work done per unit charge in moving a +ive charge from infinity to a point in the electrical field
gravitational potential
work done per unit mass in moving a mass from infinity to a point in the gravitational field
escape velocity
the velocity at which the sum of an objects KE and GPE = 0
minimum speed that an object needs to escape from a gravitational field
circular orbit
GPE constant
KE constant
elliptical orbit
when satellite closer to earth
GPE lower
KE higher
state 4 situations in which no force would act on a wire or particle in a magnetic field
a wire which is parallel to a magnetic field
a particle which is moving parallel to a magnetic field
stationary particle
uncharged particle
magnetic flux density
magnetic flux per area
1 tesla
magnetic flux density required to produce a force of 1 newton on a 1 metre wire carrying 1 ampere of current at right angles to magnetic field
faradays law
induced emf = to rate of change of flux linkage
lenz law
direction of induced emf is such that it opposes the change that caused it
