Fluorescence and X rays

Physics 3ABMr. D. Patterson

Outcomes• explain fluorescence and the

generation of X-rays—this includes applying the relationships:

Relevance of fluorescence and X-rays

Bohr’s model

HYDROGEN

Fluorescence• Ways to emit light from atoms in a

gas:–Heat it up– Apply an electric current–Hit it with light or other EMR

Fluorescence• Fluorescence is the emission of light

caused by the absorption of EMR–Wavelengths are equal or longer than

incident EMR – Energy is less or equal to incident EMR

Fluorescent lights

Whiter whites with fluorescence

X-rays• X-rays are very high energy EMR

that have high frequency and good penetrating ability

• Frequency is between 1017 and 1019 Hz

Penetrating ability of X-rays• X-rays penetration

ability is proportional to density

Detector

Source

Dangers of X-raysThey have the

ability to ionise atoms– Can cause

cancerous cell growth through damaging DNA

X-ray production• X-rays are produced by fast moving electrons

suddenly losing their kinetic energy, releasing photons (X-rays)

X-ray spectrum

Continuous spectra and line emission spectra superimposed