Final answer:
Intensity refers to the power per unit area carried by a wave, which in physics has units of W/m². It is a key concept for understanding how much energy is carried by waves such as light and sound or the strength of a magnetic field.
Step-by-step explanation:
The quality or condition of being intense corresponds to the option d. Intensity. In physics, intensity is a very specific term that refers to the power per unit area carried by a wave. This is closely related to the amplitude of a wave and can manifest in various forms, such as the brightness of light or the loudness of sound. When describing magnetic fields, intensity can also refer to the power of an electric or magnetic field per unit area, for example in terms of Watts per square meter (W/m²).
Intensity is crucial in understanding how much energy a wave carries across an area and is directly proportional to the square of the amplitude of the wave. The formula for intensity I is generally expressed as power divided by area, having units of W/m². This concept is not only important in physics but also in other fields like engineering and environmental science, where it can be applied to assess energy intensity as a measure of efficiency relative to an economy's size or resource use.