Infrared, Visible and UV light Flashcards
Why does bread toast in a toaster rather than getting generally warmer?
The toaster emits infrared radiation, which doesn’t penetrate the surface of the object, and infrared radiation is easily absorbed by the surface of objects
What are optical fibres?
Thin glass fibres used to transmit signals carried by light or infrared rays. Light waves can’t escape the fibre as when they reach the surface of the fibre, they’re reflected back into it
Compare the benefits of optical fibres to radio and microwaves
- They can carry more information as light has a shorter
wavelength than radiowaves, so can carry more pulses of
waves. - They are more secure as the signal remains in the fibre,
as light has a shorter wavelength and therefore spreads
out less
What are some uses of optical fibres?
To carry telephone and cable TV signals
Describe how UV light is used in energy efficient bulbs
UV light is created in the bulb, as it has a lower wavelength, it carries more energy than visible light. The energy of the UV light is absorbed by the internal surface of the bulb and converted into visible light. This requires much less energy than a normal lightbulb.
What are some uses of UV light?
- Sun tanning (e.g. tanning beds)
- Energy efficient light bulbs
What are some risks of UV radiation?
Can lead to:
- Skin cancer
- Premature skin aging
Describe uses of Infrared radiation in communications
- (TV/Video/DVD) Remote controls
- (Short range) data transmissions e.g. linking computer peripherals
- Optical fibre signals
Stars emit all types of electromagnetic waves. Telescopes that monitor X-rays are
mounted on satellites in space.
Why would an X-ray telescope based on Earth not be able to detect X-rays emitted
from distant stars?
X rays cannot penetrate the Earth’s atmosphere and are absorbed by it
