The radioisotope used in industrial radiography for the rapid checking of faults in welds and casting is

Analysis

The question asks for the specific radioisotope utilized in industrial settings to inspect the structural integrity of welds and metal castings. This process is known as industrial radiography.

Concept Explanation

Industrial radiography is a non-destructive testing (NDT) method. It works similarly to an X-ray: a radioactive source emits gamma rays that pass through a material (like a weld or a metal casting). If there is a crack, void, or fault in the material, the radiation passes through more easily at that point, creating a darker image on the film placed behind the object.

To be effective for thick metals, the radioisotope must:

1. Emit high-energy gamma rays (to penetrate dense materials).
2. Have a relatively long half-life (so the source doesn't need to be replaced too frequently).

Step-by-Step Solution

• Option A (Carbon-14): Primarily used for radiocarbon dating of organic materials (fossils, wood, etc.). It is not suitable for industrial metal radiography.
• Option B (Phosphorus-32): Used in medicine and agricultural research as a tracer to study plant metabolism and in the treatment of certain blood disorders.
• Option C (Cobalt-60): This isotope is a strong gamma-ray emitter. Its high energy allows it to penetrate thick steel and other metals, making it the standard choice for industrial radiography to detect faults in welds and castings.
• Option D (Iodine-131): Used extensively in medicine for diagnosing and treating thyroid conditions. It is not used for industrial metal inspection.

Conclusion

Based on the properties of these isotopes, Cobalt-60 is the correct radioisotope used for industrial radiography.

Exam Tip

When dealing with radioactivity questions in JAMB, remember these common associations:

• Carbon-14: Dating ancient organic matter.
• Cobalt-60: Industrial radiography (welds/castings) and cancer therapy.
• Iodine-131: Thyroid treatment.
• Phosphorus-32: Agricultural research/tracers.