Quiz on Particle Physics

Which type of radiation is a photon?

• α-particle

• β⁻-particle

• γ-ray

• β⁺-particle

An α-particle has:

• Charge +2e and mass ≈4 × proton

• Charge 0 and mass 0

• Charge -e and mass ≈1/1840 × proton

• Charge +e and mass ≈1/1840 × proton

Typical speed ranking, slowest to fastest:

• α (10⁶ m/s) < β (10⁸ m/s) < γ (3×10⁸ m/s)

• γ < β < α

• β < α < γ

• α < γ < β

Which will penetrate furthest?

• α through paper

• β through 1 mm Pb (lead)

• γ through several cm Pb (lead)

• α through air

How were α-particles identified?

• By their annihilation signature

• By deflection in electric/magnetic fields

• By detecting neutrinos

• By cloud chamber track lengths alone

An α-particle is identical to:

• A helium-3 nucleus

• A helium-4 nucleus

• A proton plus two neutrons separate

• A positron plus a neutron

In β⁻-decay, a neutron becomes:

• A proton + electron + antineutrino

• A proton + positron + neutrino

• A proton + gamma photon

• A proton + electron only

In β⁺-decay, a proton becomes:

• A neutron + electron + antineutrino

• A neutron + positron + neutrino

• A neutron + gamma photon

• A neutron + neutrino only

When a positron meets an electron they:

• Fission into smaller particles

• Annihilate, producing two γ-photons

• Form a stable helium atom

• Emit β-particles

1 eV equals:

• 1.60×10⁻¹⁹ J

• 1 J

• 1 keV

• 1.60×10⁻¹⁶ J