Ultraviolet (T3) Flashcards
1
Q
Describe ultraviolet…
A
- found naturally in sunlight
- we cannot see or feel UV radiation but our skin responds by turning darker
- this happens as our bodies attempt to reduce the amount of UV reaching deeper skin tissues
- darker skin absorbs more UV light, so less UV radiation reaches deeper tissues
- whilst a little is good for you (about 20 mins exposure in a sunny day) too much carries the risk of causing skin cancer
- overexposure at high altitudes (like when skiing or climbing in the Alps) or any exposure to the light from arc welding will cause a painful condition known as snow blindness, or arc eye
2
Q
How was ultraviolet discovered?
A
- following Herschel’s work, John Ritter (1776 - 1810) tried to find invisible rays at the violet end of the spectrum
- he used silver chloride which turns black when exposed to light
- the happened fastest when exposed to the visible rays at the violet end of the spectrum
3
Q
What are the three main types of ultraviolet radiation and their effects
A
- UV C
- high frequency
- causes severe damage to cells
- UV B
- high frequency
- causes severe sunburn and damage to cells
- UV A
- low frequency
- weaker effects than UV B
4
Q
List four uses of ultraviolet…
A
- security marking
- fluorescent lamps
- detecting forged bank notes
- disinfecting water