Wave Properties and the Electromagnetic Spectrum
Waves transfer energy without moving matter. Transverse waves (like water ripples) vibrate perpendicular to their direction, whilst longitudinal waves (like sound) vibrate parallel to their direction with compressions and rarefactions. The key equation connects wave speed, frequency, and wavelength.
Electromagnetic waves form a continuous spectrum from radio waves to gamma rays, all travelling at 3×10⁸ m/s through a vacuum. Your eyes detect visible light, but the full spectrum includes radio, microwaves, infrared, ultraviolet, X-rays, and gamma rays - each with different properties and uses.
These waves can be absorbed, transmitted, refracted, or reflected depending on the material and wavelength. Refraction happens when waves change speed entering different materials. Some EM waves are dangerous: infrared causes burns, UV increases skin cancer risk, and X-rays plus gamma rays are ionising radiation that can cause mutations.
💡 Real World: Your mobile phone uses microwaves, your TV remote uses infrared, and hospitals use X-rays - all part of the same electromagnetic spectrum!