Antiparticles, photons and annihilation Quiz
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5 questions, one answer each
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1. What is the charge of an antiproton?
- A. +1e
- B. 0
- C. −1e
- D. −2e
2. An electron and positron at rest annihilate to give two photons of equal energy. What is the energy of each photon?
- A. 0.256 MeV
- B. 0.511 MeV
- C. 1.022 MeV
- D. 938 MeV
3. What is the minimum photon energy needed to produce a proton–antiproton pair (rest energy of proton 938 MeV)?
- A. 469 MeV
- B. 938 MeV
- C. 1407 MeV
- D. 1876 MeV
4. Which expression gives the energy of a photon in terms of wavelength?
- A. hλ
- B. h/(cλ)
- C. hc/λ
- D. λ/(hc)
5. A photon of energy 2.0 MeV produces an electron–positron pair. What is the total kinetic energy of the pair?
- A. 0.98 MeV
- B. 1.49 MeV
- C. 2.0 MeV
- D. 1.02 MeV