What does an alternating voltage applied to an aerial emit?
An alternating voltage applied to an aerial emits radio waves of the same frequency as the alternating voltage.
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What is the radio and microwaves spectrum split into?
The radio and microwave spectrums are split into different bands which are used for different communication purposes.
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The shorter the wavelengths of the waves... [carry on]- info,range,spread?
The shorter the wavelength of the wave, the more information they carry, the shorter the range and the less they spread out.
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How do mobile phones communicate with a local mobile phone mast?
Mobile phones communicate with a local mobile phone mast using wavelengths just on the border between radio waves and microwaves.
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What harm is caused by radiation from mobile phones?
Some scientists think that the radiation from mobile phones may affect the brain, especially in children
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What are optical fibres?
Optical Fibres are very thin glass fibres.We use them to transmit signals carried by visible light or infrared radiation. The signals travel down the fibre by repeated total reflection.
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How are optical fibres useful in communications?
Optical Fibres carrying visible light or infrared are useful in communications because they carry much more information and are much more secure than radio and microwave transmissions.
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Other cards in this set
Card 2
Front
What is the radio and microwaves spectrum split into?
Back
The radio and microwave spectrums are split into different bands which are used for different communication purposes.
Card 3
Front
The shorter the wavelengths of the waves... [carry on]- info,range,spread?
Back
Card 4
Front
How do mobile phones communicate with a local mobile phone mast?
Back
Card 5
Front
What harm is caused by radiation from mobile phones?
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