a) Energy/mass
a) Einstein’s mass-energy equation; ΔE = Δmc2
b) energy released (or absorbed) in simple nuclear reactions
c) creation and annihilation of particle-antiparticle pairs
ΔE = Δmc2
change in energy (J) = change in rest mass (kg) × speed of light in a vacuum2 (m2s-2)
the implication
energy and mass are equivalent
the conservation of mass and energy during radioactive decay
a nucleus decays
its rest mass converts to kinetic energy
which is transferred to the decay products
the rest mass of the parent nucleus > the rest mass of the decay products
the conservation of energy during electron-positron annihilation
the mass of the electron and the positron is converted into energy
in the form of two gamma photons
and energy is mass