Interactions

Interactions

1. EM force

   • When 2 objects interact, they exert equal and opposite forces on eachother
   • Momentum is transferred between the objects by these forces, if no other forces act on them
   • If 2 protons approach eachother, they repel and move away from eachother
   • EM force between 2 charged objects is due to exchange of virtual photons
     • Cant be seen directly
   • If intercepted, the force would be stopped acting

2. Weak nuclear force

   • Causes neutrons to change into protons and vice versa
     • Can't be due to EM force, neutrons uncharged
   • Weaker than strong force, as doesn't affect stable nuclei
   • In beta + and - decay, a particle and antiparticle pair is produced
     • Not corresponding
   • Neutrinos and antineutrinos hardly interact
     • Rarely, eg.
       • Neutrino can interact with neutron and change it to a proton
         • Produces an electron
       • An antineutrino can interact with a proton and change it to a neutron
         • Produces positron
       • These interactions are due to exchange of weak bosons

3. Weak bosons

   • Unlike photons
     • Non-zero rest mass
     • Short rabge (<0.001fm)
     • + or - charge

4. Beta decay

   • W+ boson decays to a Beta+ particle
   • W- boson decays to a Beta - particle

5. Electron capture

   • Proton in a proton rich nucleus turns into a neutron as a result of interacting through the weak interaction with an inner-shell electron from outside the nucleus
   • W+ boson changes the electron into a neutrino
   • Same change can happen when a proton and electron collide at very high speed