Final answer:
The amplitude of a light wave determines our perception of brightness, which is measured in candelas. Similar to sound, where amplitude affects loudness, in light, amplitude affects the intensity, but other factors like wavelength and the sensitivity of the eye can also play a role.
Step-by-step explanation:
The amplitude of a sound wave is directly related to our perception of loudness, where a larger amplitude corresponds to a louder sound. In the context of light waves, amplitude is perceived as the intensity, or brightness, of the light. The standard unit for measuring the intensity of light is the candela, which compares to the luminous intensity of a standard candle.
It is important to note that while amplitude is associated predominantly with loudness in sound, our perception can be influenced by both amplitude and frequency. Sounds with frequencies at the extreme ends of the hearing range often seem less loud due to the varying sensitivity of the human ear at different frequencies. Similarly, in light, the perception of brightness can be affected by factors such as the wavelength of the light and the sensitivity of the human eye.
The concept of loudness in sound is measured in decibels (dB), and for light, the intensity or brightness does not have a specific unit like decibels; instead, the candela is used to quantify the luminous intensity of light sources.