Which quantity is defined as power divided by beam area?

Which quantity is defined as power divided by beam area?

• A. Intensity
• B. Amplitude
• C. Frequency
• D. Wavelength

Answer: (A)

Think about how much power is arriving per unit area of the beam. Intensity is that power density: if a beam has total power P and a cross-sectional area A, the average intensity is P divided by A. This tells you how bright or energetic the beam is at that location. If you spread the same power over a larger area, the intensity drops; if you raise the power while keeping the area the same, the intensity increases. The units are watts per square meter. The other terms describe different properties: amplitude is about the wave’s height, frequency is how often it repeats each second, and wavelength is the spatial distance between peaks. So the quantity defined as power divided by beam area is intensity.

Think about how much power is arriving per unit area of the beam. Intensity is that power density: if a beam has total power P and a cross-sectional area A, the average intensity is P divided by A. This tells you how bright or energetic the beam is at that location. If you spread the same power over a larger area, the intensity drops; if you raise the power while keeping the area the same, the intensity increases. The units are watts per square meter. The other terms describe different properties: amplitude is about the wave’s height, frequency is how often it repeats each second, and wavelength is the spatial distance between peaks. So the quantity defined as power divided by beam area is intensity.