Physics 2010 JAMB Past Questions - Question 18: Heat is radiated by all hot objects in the form of

Correct Answer

C

Explanation

Heat is radiated by all hot objects in the form of electromagnetic radiation, primarily in the infrared spectrum. This process is known as thermal radiation. When an object is heated, its atoms and molecules gain energy and become more agitated. As a result, they emit electromagnetic waves, which carry energy away from the object. The wavelength of these emitted waves is primarily in the infrared region of the electromagnetic spectrum, although it may extend into the visible and even ultraviolet ranges for extremely hot objects.

This thermal radiation is how the Sun, for example, emits heat and light, and it's also how heated objects like stovetops, incandescent light bulbs, and even our own bodies emit heat energy into the surrounding environment. The specific wavelength and intensity of the radiation depend on the temperature of the object, as described by Planck's law of black-body radiation. Cooler objects emit longer-wavelength infrared radiation, while hotter objects emit shorter-wavelength radiation, and the total amount of radiation emitted increases with temperature.