Which instrument is used to detect radiation from radioactive isotopes? (A) pH meter (B) Geiger counter (C) Ion-selective electrode (D) Atomic absorption spectrophotometer (AAS) - HSC - SSCE Chemistry - Question 3 - 2003 - Paper 1

To determine which instrument is used to detect radiation from radioactive isotopes, we can analyze the options provided:

1. pH meter: This instrument is used to measure the acidity or alkalinity of a solution and cannot detect radiation.

2. Geiger counter: This is a well-known device specifically designed to detect ionizing radiation, including alpha, beta, and gamma radiation. It is widely used in laboratories and in the field to monitor radiation levels.

3. Ion-selective electrode: This instrument is used for measuring concentrations of specific ions in solutions and is not capable of detecting radiation.

4. Atomic absorption spectrophotometer (AAS): This device is mainly used to analyze the concentration of metals in a sample and does not detect radiation.

Based on the analysis, the best answer is (B) Geiger counter.