Physics period 8 / Samuella Boateng
Ultraviolet Light Information
- Ultraviolet light description
-An ultraviolet light is a type of electromagnetic radiation, as are radio waves, Infrared radiation, X-rays and Gamma-rays. UV light comes from the sun, and is invisible to the naked human eye.
- Wavelength range
- Ultraviolet light falls in the range of the EM spectrum between visible light.
There are three different types of Uv light.
Ultraviolet C (UVC)
200 - 290 nanometers
Ultraviolet B (UVB)
290 - 320 nanometers
Ultraviolet A (UVA)
320 - 400 nanometers
- Frequency Range
Ultraviolet radiation is absorbed by Ozone at an altitude of between 20 and 40 km.
- Velocity in a vacuum
-Electromagnetic waves all travel at the same constant speed as light( speed of light-300,000,000), 186,000 miles per second in a vacuum. All electromagnetic waves have the same form and travel at the same speed, but differ in wavelength.
- Key facts-UVA is the least harmful but can contribute to the aging of skin, DNA damage and possibly skin cancer. UVB rays are the ones that burn the skin and can damage the eyes.
- Key facts-Medical Equipment like surgical scissors can be sterilised using UV rays.
Ultraviolet Light in Life
Ultraviolet lights are used in Tonic water, vitamins and drugs, chlorophyll, toothpaste and whiteners. Antifreeze, laundry detergent, honey and paper.
Ultraviolet lights is are used for killing Microbes, sterilizing food and drugs. And treat vitamin D deficiency, and some skin disorders.
Positive Health Impact- Several human skin diseases, like psoriasis, vitiligo, atopic dermatitis and localized scleroderma, can be treated with solar radiation
Positive Health Impact- (Triggers vitamin D) – UV from the Sun is needed by our bodies to produce vitamin-D. Vitamin-D helps strengthen bones, muscles and the body's Immune system, It may also lower the risk of getting some kinds of cancers such as colon cancer.
Negative Health Impact- (Damages eyes) - Prolonged exposure to UV damages the tissues of the eyes , and can cause a "burning" of the eye surface, this increases the chance of getting a cataract(s)(which can cause blindness).
Negative Health Impact- (Ages skin) – UV speeds up the aging of skin, since the UV destroys collagen and connective tissue beneath the top layer of the skin. This causes wrinkles, brown 'liver’ spots and loss of skin elasticity.