Karteikarten
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- 1How do thermograms use colour?Temperatures are represented by a range of colours.
• hot => white/yellow/red
• cold => black/dark blue/purple - 2What is the wave equation?An equation used to work out the speed of a wave, just by knowing its frequency and wavelength.
- 3Work out the wavelength of a wave, if Invicta FM broadcasts have a frequncy of 103 MHz Electromagnetic waves' (speed) = 300,000,000 m/sF = 103,000,000 Hz = 103 x 10 Hz
- 4Draw a ray diagram to show refraction: E.g. (When light goes from a less dense material (e.g. air) to a denser medium (e.g. glass) then the ray bends towards the normal - (light slows down)).
- 5Draw a ray diagram to show reflection: (E.g. Sound - echoes are made when sound waves a reflected off of (bounced back of) a surface. Harder surfaces reflect sound better than soft).
- 6Draw a diagram to show how light can travel along an opitcal fibre:
- 7Explain how information can be transmitted, using light and infrared signals by an optical fibre?The little light absorbed by the glass enters at one end undergoes repeated TIR, and comes out the other.
Information (e.g. telephone calls, data etc) can be converted into either visible light signals or infrared signals, and transmitted by optical fibres. - 8How are lasers (beams) used in CD players?They are used to read information from CDs in CD players. A CD's shiny surface contains microscopic pits in a spiral track. The pattern of the pits contains digital information. The laser light is reflected off the surface of the CD as the disk spins.
- 9Risks of mobile phones: (Evidence of dangers/risks is inconclusive)• Microwaves from the phone can penetrate body tissues (of a few cm) causing a 0.1°C decrease of body heat.
• Mobile phone masts can cause DNA damage, cancers (eye), cardiac problems etc.
- 10Risks of mobile phones: (Evidence of dangers/risks is inconclusive)• Health effects = Mobile phone usage can cause changes in brain activity, reaction times, and sleep patterns.
- 11How can you reduce signal loss with microwaves?• Reduce the distance the microwaves have to travel.
• Increase the wavelength. - 12How do the signals from an infrared remote control a device?Infrared remotes control devices by sending signal pulses of infrared light to a device.
- 13Why is it easier to remove noise from digital signals?Because digital signals are either on (1) or off (0), it still clear what state the signal is in. Meaning that noise can be removed and the signal can still be returned to its orginal state.
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- Karteikarten am Ohne Titel, erstellt von tmosh8000 am 05/01/2015.
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