Absorption and Reflection
A substance can do the following to a wave when hit: absorb, transmit, refract or reflect. Substances will do different things according to the wavelength.
For example, a block of wood
- will reflect light from the visible light spectrum.
- will absorb infrared, increasing its temperature
- let radio waves travel straight through and be transmitted out the other side.
Different parts of the EM spectrum have different dangers associated with them:
- Radio waves - None
- Microwaves - Internal heating of body cells
- Infrared - Skin burns
- Visible light - None - though if very intense can cause blindness
- Ultraviolet - Damage to surface cells and eyes leading to cancer and__ eye conditions__
- X-rays - Mutation or damage to cells in the body
- Gamma rays - Mutation or damage to cells in the body
Different parts of the EM spectrum have different uses:
- Radio waves - Broadcasting, communications and satellite transmissions
- Microwaves - Cooking, communications and satellite transmissions
- Infrared - Cooking, thermal imaging, short range communications, optical fibres, television remote controls and security systems.
- Visible light - Vision, photography and illumination
- Ultraviolet - Security marking, fluorescent lamps, detecting forged bank notes and disinfecting water
- X-rays - Observing internal structure of objects, airport security scanners and medical x-rays
- Gamma rays - Sterilising food and medical equipment and the detection of cancer and its treatment
Atoms and nuclei have the ability to absorb and __transmit __a part of the EM spectrum.
- Where in the atom are gamma rays produced?
- Can infrared be used for cooking and detecting forged bank notes?
- What four things can a substance do with the EM spectrum that is incident upon it?
- Your answer should include: Absorb / transmit / reflect / refract