Karteikarten
core science physics unit 2
Karten in diesem Stapel (19)
- 1how many types of electromagnetic waves are there?7
- 2what is the electromagnetic spectrum and their wave lengths?radio waves- 1m - 10^4m
micro waves- 10^-2 (1cm)
infra red- 10^-5 (0.01mm)
visible light- 10^-7m
ultra violet 10^-8m
x-rays- 10^-10m
gamma rays- 10^-12m - 3what are all em waves?transverse waves
- 4what do all different em waves do?travel at the same speed (3x10^8 m/s)- in a vacuum eg space
- 5what do em waves with higher frequencies have?shorter wave lengths
- 6when and who discovered infrared radiation?1800
Herschel - 7how did Herschel discover infrared radiation?when experimenting with sunlight and a prism, before this scientists thought visible light was the only part of the em spectrum
- 8describe the experiment Herschel did when he discovered infrared radiation1- when white light goes through a prism, it creates a spectrum of colors, Herschel used this experiment to create a picture on the screen.
2- He wanted to know about the amount of heat in each of the colors, he used a thermometer to do this and noticed an increase in temperature from violet to red
3- He then measured the temperature just past the red part of the spectrum where there was no visible light. He found this part of the spectrum had the highest temperature of all-he had discovered infrared, an invisible type of radiation - 9when and who discovered ultraviolet radiation?1801
Ritter - 10how did Ritter discover ultra violet?he wanted to find out if there was anything the other end of the spectrum to what Herschel had tested this was past violet
1.Ritter knew that silver chloride turned from white to black when exposed to light, so he decided to measure how quickly silver chloride coated strips changed when exposed to different colors of light
2. in a dark room he created a spectrum using a light source and a prism and exposed the strips of paper to each color. he timed how long it took the strips to turn black
3. the strips changed quickest when exposed to light nearer the blue end of the spectrum
4. he then placed a strip in an area just past the violet part of the spectrum - here he saw the quickest change of all and knew he had discovered ultra violet radiation, an invisible form of light - 11on the em spectrum what does a higher frequency mean in a wave?the more energy the radiation has and the more harmful the radiation is
- 12how can microwaves be harmful to humans?microwaves have the same vibrations of many molecules, and so increase these vibrations - resulting in heating. Microwaves can heat human body cells this way. Mobile phones use microwaves, and their increasing use has caused concerns, as the handset is often held close to the brain. There have been suggested links with brain tumors but nothing has been proved.
- 13how is infrared harmful to humans?the infrared range of frequencies can make the surface molecules of any substance vibrate- this has a heating effect. Infrared radiation has a higher frequency than microwaves, so carries more energy. If a human body is exposed to too much infrared radiation it can cause nasty skin burns
- 14how is Ultraviolet radiation dangerous to humans?it is ionising and carries enough energy to knock electrons off atoms. Sunburn happens when surface skin cells have been damaged b absorbing UV rays in sunlight. This can cause cell mutation or destruction and skin cancer. The UV in sunlight can also cause eye damage.
- 15how are gamma rays and x rays harmful to humans?they are very high frequency waves and are also ionising. they carry a lot of energy this means they can be very damaging and penetrate further into the body. they can cause cell mutation or destructing leading to tissue damage or cancer.
- 16what are radio waves mainly used for?communications
tv and radio signals
transmit satellite signals - 17what are microwaves used for?satellite radiation
mobile phones - 18what is infrared used for?monitor temperature
toasters
remote controls
mobile phones and computures(only short distances)
sensors used in security systems - 19what uses infrared to transmit data?optical fibres- they can carry data over long distances eg- telephone cables
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- Karteikarten am core science physics unit 2, erstellt von elsa003 am 31/03/2015.
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