IGCSE Physics Practice Exam 2025 - Free International General Certificate of Secondary Education Practice Questions and Study Guide

Microwaves are electromagnetic waves with wavelengths ranging from one meter to one millimeter, or frequencies between 300 MHz and 300 GHz. One of the most common applications of microwaves is in heating processes, such as with microwave ovens. These devices use microwaves to agitate water molecules in food, resulting in heat and cooking. Additionally, microwaves can be employed in various monitoring temperature applications, such as non-contact thermometers that measure the thermal radiation emitted by objects.

In contrast, photography relies on visible light, not microwaves, to capture images. Fluorescent lamps utilize gas discharge and not microwave radiation to generate light. While satellite communication does utilize microwaves to transmit data, the question specifically seeks an application that encompasses the heating and monitoring capabilities that microwaves provide. Thus, the answer reflecting the common usage of microwaves in both heating processes and temperature monitoring aligns with their fundamental properties and applications.