Question

ow can a scientist assess whether a pure niobium (Nb) sample is responsible for contaminating the lab with radioactivity?
Test the niobium sample to see whether it now contains other elements.
Test the niobium sample for the presence of niobium oxide compounds.
Heat the niobium, and see if the level of radioactivity in the lab increases.
Place the niobium under pressure, and see if the level of radioactivity in the lab increases.

Answer 1

Best choice from your list: "Test the niobium sample to see whether it now contains other elements."

Why:
- Radioactivity comes from radioactive isotopes (impurities or activation products), not from the chemical form of niobium. So look for contaminant radionuclides (U, Th, Cs, Co, activated Nb isotopes, etc.) or surface contamination.
- The presence of oxides (niobium oxide) does not by itself imply radioactivity — oxide vs metal is a chemical difference, not a nuclear one.
- Heating or pressurizing the sample will not create radioactivity and could be unsafe; they are not reliable diagnostic tests for identifying a radioactive contaminant.

Recommended safe steps (high level):
- Survey the lab and the sample with appropriate radiation detectors (gamma spectroscopy, alpha/beta counters, Geiger/ion chamber depending on suspected emissions) to confirm and identify any emissions.
- Do wipe/smear tests of the sample surface and nearby surfaces and count those wipes to detect removable contamination.
- Perform chemical/elemental analysis (e.g., ICP-MS or similar) or gamma spectrometry to identify specific radionuclides or trace elemental contaminants.

If you want, I can summarize which detectors are suited for alpha/beta/gamma, or what a wipe test indicates.