Which term describes the rate of energy transfer by a wave?

• A. Energy
• B. Wavelength
• C. Power
• D. Intensity

Answer: (C)

The key idea is that power is the rate at which energy is transferred. In waves, power tells you how much energy passes a point (or through a surface) every second, measured in watts. Wavelength is about the spatial distance between repeating features in the wave and doesn’t say how fast energy moves. Energy is the total amount carried, not the rate at which it is delivered. Intensity describes how much energy passes through a unit area per unit time, which is related to power but depends on the area you’re considering; it’s not the total rate itself. So the term that describes the rate of energy transfer by a wave is power.