Wave nature of light:
Light behaves as a wave, oscillating in electric and magnetic fields. These oscillations can be characterized by:
- Wavelength (λ): The distance between two consecutive peaks of the wave.
- Frequency (f): The number of cycles (peaks) passing a point per second.
- Speed (v): The rate at which the wave propagates.
Electromagnetic spectrum:
Visible light is just one small part of the electromagnetic spectrum, which includes a range of frequencies and wavelengths:
- Low frequencies: Radio waves, microwaves, and infrared radiation have longer wavelengths and lower frequencies.
- High frequencies: Ultraviolet radiation, X-rays, and gamma rays have shorter wavelengths and higher frequencies.
Constant speed of light:
In a vacuum, all electromagnetic waves travel at the same speed, approximately 299,792 kilometers per second (c). This constant value ties together the three properties of light waves:
c = λf
This equation tells us that the product of wavelength and frequency is always constant for a particular wave. So, if the wavelength changes, the frequency must change inversely to maintain the constant product.
Red vs. Violet light:
- Red light: Longer wavelength (around 700 nm) corresponds to a lower frequency (around 430 THz).
- Violet light: Shorter wavelength (around 400 nm) corresponds to a higher frequency (around 790 THz).
Energy and frequency:
The energy carried by a single packet of light (a photon) is directly proportional to its frequency. Higher frequency translates to higher energy photons. This explains why violet light, with its higher frequency, carries more energy compared to red light.