An electromagnetic wave and a light wave are essentially the same thing. "Light" typically refers to the subset of electromagnetic waves that are visible to the human eye, while "electromagnetic waves" encompass a broader spectrum of energy, including radio waves, microwaves, infrared, ultraviolet, X-rays, and gamma rays.
The distinction between electromagnetic waves and light waves arises from the specific range of frequencies or wavelengths they occupy within the electromagnetic spectrum. Light waves fall within the visible range of the spectrum, which is approximately 400 to 700 nanometers in wavelength. Other electromagnetic waves have different wavelengths and frequencies.
The main factor that determines the differences between various types of electromagnetic waves is their wavelength and frequency. Wavelength is the distance between two consecutive peaks or troughs of a wave, while frequency is the number of complete wave cycles occurring per second. The relationship between wavelength and frequency is inversely proportional: longer wavelengths correspond to lower frequencies, and shorter wavelengths correspond to higher frequencies.
While all electromagnetic waves, including light waves, carry energy and information through oscillations of electric and magnetic fields, they differ in their interactions with matter. Light waves within the visible range are more easily detected by our eyes, but other electromagnetic waves, such as X-rays or radio waves, have different properties and interact with matter in different ways. For example, X-rays can penetrate through soft tissues but are absorbed by denser materials like bones, making them useful for medical imaging. Radio waves can be used for long-distance communication due to their ability to travel through the atmosphere and interact with antennas.
In summary, the difference between an electromagnetic wave and a light wave lies in the specific range of frequencies or wavelengths they occupy within the electromagnetic spectrum. While all electromagnetic waves share the same fundamental nature as energy transfer in wave form, they exhibit distinct characteristics and interactions with matter based on their wavelength and frequency.