Which of the following devices is commonly used to measure radiation exposure?

The Geiger-Muller counter is a widely used instrument for measuring radiation exposure because it is specifically designed to detect and quantify ionizing radiation. This device operates by using a Geiger-Muller tube filled with a low-pressure inert gas, which becomes ionized when radiation passes through it. The resulting ionization creates an electric current that can be counted and displayed as a measure of radiation exposure. The Geiger-Muller counter is particularly effective because it can detect alpha, beta, and gamma radiation, making it versatile for various applications, including monitoring environmental radiation, assessing workplace safety, and conducting research.

In contrast, while thermometers measure temperature and are essential in many scientific and medical applications, they do not provide any information about radiation levels. Biosensors are used primarily to detect biological molecules or pathogens, which makes them irrelevant for measuring radiation exposure. Radiometers, on the other hand, are typically used to measure the power of electromagnetic radiation, such as light or infrared radiation, rather than ionizing radiation specifically. Thus, the Geiger-Muller counter stands out as the most appropriate tool for measuring radiation exposure among the listed options.