A β+\beta^+β+ particle (positron) is a fast-moving positive electron. Which statement explains how β+\beta^+β+ particles are emitted from a radioactive atom?
An electron is emitted as a β+\beta^+β+ particle from an inner electron shell of the atom.
An electron is emitted as a β+\beta^+β+ particle from an outer electron shell of the atom.
A proton changes into a neutron and a β+\beta^+β+ particle is emitted from the nucleus.
A neutron changes into a proton and a β+\beta^+β+ particle is emitted from the nucleus.
484 exam-style questions on CIE IGCSE Physics 5.2 Radioactivity, covering 5.2.1 Background radiation and measuring count rate, 5.2.2a Alpha, beta and gamma emission, 5.2.2b Deflection and ionising effects of nuclear radiation, 5.2.3a Radioactive decay, 5.2.3b Effects of decay on the nucleus and decay equations, 5.2.4a Half-life, 5.2.4b Choosing isotopes for applications, and 5.2.5 Effects of ionising radiation and safety precautions. Each one has a worked solution and a mark scheme showing where the marks go.