Light and the electromagnetic spectrum
Spectroscopy is the analysis of the electromagnetic radiation (light) absorbed or emitted by substances. Because light absorption by a substance can be correlated with its structure, chemists use spectroscopy to aid them in deducing the structure of unknown compounds.
Light has wave properties with characteristic wavelengths and frequency (see diagram). Light also carries energy in the form of tiny particles known as photons.
The range of wavelengths and frequencies in light is known as the electromagnetic spectrum. The diagram shows that the spectrum is divided into various regions.
Light has wave properties with characteristic wavelengths and frequency (see diagram). Light also carries energy in the form of tiny particles known as photons.
The energy of the photons is related to the frequency (ν) and wavelength (λ) of the light through the two equations shown (h is Planck's constant and c is the speed of light).
The range of wavelengths and frequencies in light is known as the electromagnetic spectrum. The diagram shows that the spectrum is divided into various regions.
Coloured substances absorb visible light.
We feel warm on a sunny day due to molecules in our skin absorbing infrared radiation from the sun.
Excessive exposure to ultraviolet radiation causes skin cancer.
We feel warm on a sunny day due to molecules in our skin absorbing infrared radiation from the sun.
Excessive exposure to ultraviolet radiation causes skin cancer.