DP Physics Questionbank

Description

Nature of science:

Paradigm shift: Einstein realized that the law of conservation of momentum could not be maintained as a law of physics. He therefore deduced that in order for momentum to be conserved under all conditions, the definition of momentum had to change and along with it the definitions of other mechanics quantities such as kinetic energy and total energy of a particle. This was a major paradigm shift. (2.3)

Understandings:

• Total energy and rest energy
• Relativistic momentum
• Particle acceleration
• Electric charge as an invariant quantity
• Photons
• MeV c ^–2 as the unit of mass and MeV c ^–1 as the unit of momentum

Applications and skills:

• Describing the laws of conservation of momentum and conservation of energy within special relativity
• Determining the potential difference necessary to accelerate a particle to a given speed or energy
• Solving problems involving relativistic energy and momentum conservation in collisions and particle decays

Guidance:

• Applications will involve relativistic decays such as calculating the wavelengths of photons in the decay of a moving pion 
• The symbol m ₀ refers to the invariant rest mass of a particle
• The concept of a relativistic mass that varies with speed will not be used
• Problems will be limited to one dimension

Data booklet reference:

Theory of knowledge:

• In what ways do laws in the natural sciences differ from laws in economics?

Utilization:

• The laws of relativistic mechanics are routinely used in order to manage the operation of nuclear power plants, particle accelerators and particle detectors

Aims:

• Aim 4: relativistic mechanics synthesizes knowledge on the behaviour of matter at speeds close to the speed of light
• Aim 9: the theory of relativity imposes one severe limitation: nothing can exceed the speed of light

Directly related questions

• 16N.3.HL.TZ0.8c:

  Calculate the energy and the momentum for each photon after the collision.

• 16N.3.HL.TZ0.8b:

  Determine the speed of the incoming electron.

• 16N.3.HL.TZ0.8a: Explain, in terms of a conservation law, why two photons need to be created.
• 17M.3.HL.TZ1.5a:

  Calculate the potential difference V.

• 17M.3.HL.TZ2.6:

  A lambda $\mathrm{\Lambda }$⁰ particle at rest decays into a proton p and a pion ${\pi }^{-}$ according to the reaction

  $\mathrm{\Lambda }$⁰ → p + $\pi$^–

  where the rest energy of p = 938 MeV and the rest energy of $\pi$^– = 140 MeV.

  The speed of the pion after the decay is 0.579c. For this speed $\gamma$ = 1.2265. Calculate the speed of the proton.

• 17M.3.HL.TZ1.5b:

  The proton collides with an antiproton moving with the same speed in the opposite direction. As a result both particles are annihilated and two photons of equal energy are produced.

  Determine the momentum of one of the photons.

• 20N.3.HL.TZ0.6b:

  Calculate the total energy of the deuterium particle in $\mathrm{MeV}$.

• 20N.3.HL.TZ0.6c: In relativistic reactions the mass of the products may be less than the mass of the reactants....
• 20N.3.HL.TZ0.6a: Define rest mass.
• 17N.3.HL.TZ0.7a:

  Determine the rest mass of the ${\mathrm{\Lambda }}^0$ particle.

• 17N.3.HL.TZ0.7b:

  Determine, using your answer to (a), the initial speed of the ${\mathrm{\Lambda }}^0$ particle.

• 18M.3.HL.TZ1.6b:

  State the rest mass of the pion with an appropriate unit.

• 18M.3.HL.TZ1.6a.ii:

  show that the energy of the pion is about 140 MeV.

• 18M.3.HL.TZ2.6a:

  Calculate the gamma (γ) factor for one of the protons.

• 18M.3.HL.TZ2.6b.i:

  Determine, in terms of MeV c^–1, the momentum of the pion.

• 18M.3.HL.TZ2.6b.ii:

  The diagram shows the paths of the incident protons together with the proton and neutron created in the interaction. On the diagram, draw the path of the pion.

  

• 18N.3.HL.TZ0.6b.i: Explain the origin of each equation.
• 18N.3.HL.TZ0.6a:

  Show that the momentum of the electron is 1.41 MeV c^–1.

• 18N.3.HL.TZ0.6b.ii: Calculate, in MeV c–1, p1 and p2.
• 19M.3.HL.TZ2.8bi: Determine the momentum of the proton.
• 19M.3.HL.TZ2.8a: Define total energy.
• 19M.3.HL.TZ2.8bii:

  Determine the speed of the proton.

• 19M.3.HL.TZ2.8biii:

  Calculate the potential difference V.

• 19M.3.HL.TZ1.6a:

  Show that energy is conserved in this decay.

• 19M.3.HL.TZ1.6b:

  Calculate the speed of the pion.

• 19N.3.HL.TZ0.5a(i):

  the total energy.

• 19N.3.HL.TZ0.5a(ii):

  the speed.

• 19N.3.HL.TZ0.5b:

  Determine the rest mass of X.