EL2 Flashcards
What is spectroscopy?
The study of the interaction between matter and EM radiation - many spectroscopic techniques exist.
What is the scientific principle that spectroscopy follows?
Under certain conditions, a substance can absorb or emit EM radiation in a characteristic way.
What is the main reason spectroscopy is used?
To identify atoms or elements or information about them (e.g. structure, way atoms are held together).
What EM radiation do glowing stars emit?
All the light frequencies between UV and infrared in the EM spectrum.
What does an absorption spectra look like?
Black lines on a coloured background.
What does an emission spectra look like?
Coloured lines on a black background.
What two theories are used to describe the behaviour of light?
Wave theory and the particle theory.
What is the wave theory of light?
Light is a form of electromagnetic radiation.
What is the particle theory of light?
Light is regarded as a stream of photons (tiny packets of energy).
What does the energy of a photon relate to?
Relates to the position of the light in the EM spectrum.
How is an emission spectrum produced?
Atoms becomes excited
Electrons jump to higher energy levels.
Electrons fall back to lower levels.
They emit extra energy as EM radiation.
How is an absorption spectrum produced?
Electrons jump to higher energy levels without falling back again.
