The Electromagnetic Spectrum (Chapter 11) Flashcards
Name the complete electromagnetic spectrum.
- Radio waves
- Microwave
- Infrared
- Visible light
- Ultraviolet
- X-rays
- Gamma rays
What is electromagnetic spectrum?
EM spectrum is a continuous spectrum of waves, including the visible spectrum.
What are the properties of EM spectrum waves?
- They all transfer energy
- They are all transverse wave
- They all travel at 300,000,000 m/s, the speed of light in a vacuum
- They can all be reflected and refracted
What are the sources, detectors and uses of radio waves?
Sources - radio transmitters, TV transmitters
Detectors - Radio and TV aerials
Uses - (long, medium, short-) wave radio, TV
What are the sources, detectors and uses of Microwaves?
Sources - microwave transmitters, ovens
Detectors - Microwave receivers
Uses - mobile phone and satellite communication, cooking
What are the sources, detectors and uses of Infrared wave?
Sources - Hot objects
Detectors - Skin, blackened thermometer, special photographic film
Uses - Infrared cookers, heaters, TV, stereo remote control, night vision
What are the sources, detectors and uses of Visible Light?
Sources - Luminous objects
Detectors - eyes, photographic film, light-dependent resistors
Uses - Seeing, communication, photography
What are the sources, detectors and uses of Ultra Violet?
Sources - UV lamps, Sun
Detectors - Skin, photographic film, fluorescent chemicals
Uses - Fluorescent tubes, UV tanning lamps
What are the sources, detectors and uses of X-rays?
Sources - X-ray tubes
Detectors - photographic film
Uses - x-radiography to observe the internal structure of objects
What are the sources, detectors and uses of Gamma rays?
Sources - radioactive materials
Detectors - Geiger-Müller tube
Uses - Sterilizing equipment, food processing, radiotherapy.
What is the smallest wavelength in EM spectrum?
Gamma rays
What is the longest wavelength in EM spectrum?
Radio waves
Which has the most frequency in EM spectrum?
Gamma rays
Which has the least frequency in EM spectrum?
Radio waves
Why food place in a microwave oven cooks more quickly than in a normal oven?
Because water molecules in the food absorb the microwaves and become very hot.
Microwaves can also heat body tissues.
True
The hotter the object, the ——- infrared energy it will emit.
More
Why infrared waves are not that harmful?
Because they have low penetrating power.
What is visible light from lasers used to read?
It is used to read compact discs and barcodes.
What does overexposure of infrared waves result?
Skin burnt
Which wave is used to send signals along optical fibers?
Visible light
What can overexposure of UV light result?
Damage to human eyes and skin.
How to prevent UV light exposure?
By wearing protective goggles or glasses and skin creams to block the UV rays.
Why is ozone layer important?
The ozone layer in Earth’s atmosphere absorb large quantities of the sun’s UV radiation.
Why fluorescent tubes glow?
Because the UV light they produce strikes a special coating on the inside of the tube, which then emits visible light.
What can overexposure of x-ray cause?
It can cause cancers.
What are uses of x-rays?
- To check internal structure of objects
- As part of the security checking procedures in airports
Why x-rays can be used check for broken bones?
Because they can pass easily through soft body tissue but cannot pass through bones.
Gamma rays can cause damage to living cell.
True
What does damage cause by gamma rays result?
It can cause mutation, leading to cancer.
Why can gamma rays use in food preservation?
It is used to kill microorganism to preserve food longer.
How to prevent overexposure of gamma rays?
The use of lead screens, boxes and aprons.
