**Question:** Radioactive cobalt emits:

A. beta particles
B. alpha particles
C. gamma rays
D. both beta and gamma particles

**Correct Answer:** D. both beta and gamma particles

**Core Concept:**

Radioactive substances, such as cobalt, emit radiation as they decay and lose energy. This radiation is made up of particles or waves that carry energy away from the radioactive nucleus. In the case of cobalt, it undergoes radioactive decay, specifically, the beta decay process.

**Why the Correct Answer is Right:**

Cobalt is a radioactive isotope of cobalt-60, which undergoes beta decay. During beta decay, a neutron is converted into a beta particle (an electron or positron) and an antineutrino. In addition to beta particles, cobalt-60 also emits gamma rays, which are high-energy electromagnetic waves. Gamma rays are emitted as a result of the nuclear transitions occurring during the decay process.

**Why Each Wrong Option is Incorrect:**

A. **Beta particles (Option A):** Beta particles are electrons or positrons emitted during the decay of certain radioactive isotopes, such as cobalt-60. However, beta particles are only one part of the radiation emitted by cobalt-60, not the only radiation emitted.

B. **Alpha particles (Option B):** Alpha particles are helium nuclei consisting of two protons and two neutrons, and are not emitted by cobalt-60. Cobalt-60 emits beta particles and gamma rays, not alpha particles.

C. **Gamma rays (Option C):** Gamma rays are high-energy electromagnetic waves emitted during the decay of radioactive isotopes, such as cobalt-60. However, gamma rays are not the only radiation emitted by cobalt-60, as they are produced in conjunction with beta particles.

**Clinical Pearl:**

Understanding the types of radiation emitted by radioactive isotopes like cobalt-60 is crucial for the safe handling and use of these substances in medical applications, such as radiation therapy. While cobalt-60 emits beta particles and gamma rays, it is essential to know that only one type of radiation is not enough to fully describe the radiation emitted by cobalt-60. A thorough understanding of both beta particles and gamma rays helps in proper planning and administration of cobalt-60 therapy for cancer treatment and ensures patient safety during procedures.