Radioactivity – Which of the following is a positively charged particle (radiation) emitted by a radioactive element?

Introduction / Context:
Radioactive emissions include alpha, beta, and gamma radiations, each with different charge, mass, and penetrating power. Identifying the charge helps infer shielding needs and biological impact.

Given Data / Assumptions:

• We must choose the radiation that carries a positive electric charge.
• Options mix particle and electromagnetic emissions.
• Classical definitions apply: alpha = He nuclei; beta often means electrons; gamma = photons.

Concept / Approach:
An alpha particle is a helium-4 nucleus containing 2 protons and 2 neutrons; its net charge is +2e. Beta radiation typically refers to beta-minus (electrons, charge −e), though beta-plus (positrons, +e) exists; exam convention usually treats “beta rays” as negative unless specified as positrons. Gamma radiation is neutral electromagnetic radiation, and cathode rays are streams of electrons (negative).

Step-by-Step Solution:
Recall: alpha = +2 charged, heavy; low penetration, high ionization.Beta (classical) = electrons, −1 charge; can also be positrons if stated as beta-plus.Gamma = photons, neutral.Cathode rays = electrons, −1 charge.Select the only clearly positive option: alpha ray.

Verification / Alternative check:
Deflection in electric/magnetic fields: alpha deflects towards negative plate; beta (−) towards positive plate; gamma unaffected, which corroborates charge assignments.

Why Other Options Are Wrong:

• Beta ray: conventionally negative electrons unless specified as positrons.
• Cathode ray: electrons emitted from a cathode; negative.
• Gamma ray: neutral photons; no charge.

Common Pitfalls:
Forgetting that “beta” can be either electron or positron; unless specified, exams typically mean beta-minus, which is negative. “Alpha” is unambiguously positive.

Final Answer:
Alpha ray