Nagwa uses cookies to ensure you get the best experience on our website. Learn more about our Privacy Policy.

Start Practicing

Worksheet: Subatomic Particles

Q1:

Identify the missing particle in the reaction p p n + β†’ + .

  • A e βˆ’
  • B e +
  • C 𝜈 e
  • D n
  • E 𝜈 e

Q2:

A neutral pion has a rest mass of 135.0 MeV. Assuming conservation of momentum, what is the energy of each 𝛾 ray produced in the decay of a neutral pion at rest. The reaction produces two equal energy photons.

Q3:

Consider the following decays of unstable subatomic particles: Which of these decays cannot occur because the law of conservation of lepton number would be violated?

  • A πœ‹ β†’ + 𝜈 βˆ’ βˆ’ e e
  • B p n e β†’ + + 𝜈 + e
  • C πœ‡ β†’ + 𝜈 + 𝜈 βˆ’ βˆ’ πœ‡ e e
  • D πœ‡ β†’ + 𝜈 + + e e
  • E Ξ› β†’ πœ‹ + 0 βˆ’ p

Q4:

An electron has a rest mass of 0.511 MeV. How much energy is released when an electron and a positron at rest annihilate each other?

Q5:

Identify the missing particle in the reaction p p p + β†’ + Ξ› + 0 .

  • A p
  • B Ξ› 0
  • C e +
  • D K +
  • E e βˆ’

Q6:

Consider the following decays of unstable subatomic particles: Which of these decays cannot occur because the law of conservation of lepton number would be violated?

  • A πœ‹ β†’ + 𝜈 βˆ’ βˆ’ e e
  • B p n e β†’ + + 𝜈 + e
  • C πœ‡ β†’ + 𝜈 + 𝜈 βˆ’ βˆ’ πœ‡ e e
  • D n p e β†’ + βˆ’
  • E Ξ› β†’ πœ‹ + 0 βˆ’ p

Q7:

An electron has a rest mass of 0.511 MeV. When both an electron and a positron are at rest, they can annihilate each other according to the reaction 𝑒 + 𝑒 β†’ 𝛾 + 𝛾 βˆ’ + . The energies of the photons produced in the reaction are equal to each other, as are the photon’s momenta and their frequencies.

What is the energy of one of the photons?

  • A 0.383 MeV/c2
  • B 0.475 MeV/c2
  • C 0.362 MeV/c2
  • D 0.511 MeV/c2
  • E 0.256 MeV/c2

What is the momentum of one of the photons?

  • A 2 . 7 3 Γ— 1 0 βˆ’ 2 2 kgβ‹…m/s
  • B 3 . 0 5 Γ— 1 0 βˆ’ 2 2 kgβ‹…m/s
  • C 2 . 8 8 Γ— 1 0 βˆ’ 2 2 kgβ‹…m/s
  • D 2 . 5 6 Γ— 1 0 βˆ’ 2 2 kgβ‹…m/s
  • E 3 . 2 8 Γ— 1 0 βˆ’ 2 2 kgβ‹…m/s

What is the frequency of one of the photons?

  • A 2 . 0 0 Γ— 1 0 2 0 Hz
  • B 1 . 4 1 Γ— 1 0 2 0 Hz
  • C 1 . 2 3 Γ— 1 0 2 0 Hz
  • D 1 . 6 0 Γ— 1 0 2 0 Hz
  • E 1 . 8 7 Γ— 1 0 2 0 Hz

Q8:

Identify the missing particle in the reaction K n βˆ’ 0 + β†’ Ξ› + .

  • A n
  • B Ξ› 0
  • C K +
  • D πœ‹ βˆ’
  • E 𝜈 e

Q9:

Identify the missing particle in the reaction 𝜏 β†’ + 𝜈 + + + e e .

  • A 𝜈 e
  • B e βˆ’
  • C πœ‹ βˆ’
  • D 𝜈 𝜏
  • E πœ‹ 0

Q10:

The decays of unstable subatomic particles can be described using equations: Which of the decays shown cannot occur because the law of conservation of lepton number would be violated?

  • A πœ‹ β†’ + 𝜈 βˆ’ βˆ’ e e
  • B p n e β†’ + + 𝜈 + e
  • C πœ‡ β†’ + 𝜈 + 𝜈 βˆ’ βˆ’ πœ‡ e e
  • D πœ‹ β†’ + 𝜈 + 𝜈 + + πœ‡ e e
  • E Ξ› β†’ πœ‹ + 0 βˆ’ p

Q11:

A negative pion has a rest mass of 139.6 MeV. The primary decay mode for negative pions is πœ‹ β†’ πœ‡ + 𝜈 βˆ’ βˆ’ πœ‡ . A muon has a rest mass of 105.7 MeV, while a neutrino has negligible rest mass and a momentum 𝐸 𝑐 . A pion that is at rest undergoes a primary mode decay .

How much energy is released in this decay?

How much energy does the muon take from the reaction?

How much energy does the neutrino take from the reaction?

Q12:

Identify the missing particle in the reaction 𝜈 + β†’ + e p n .

  • A e βˆ’
  • B n
  • C 𝜈 e
  • D e +
  • E p