Criado por oliviabaines
mais de 10 anos atrás
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Questão | Responda |
Electromagnetic radiation are electric disturbances -they travel as waves and move energy from place to place | -can travel through a vacuum at the same speed -have different wavelengths and frequencies |
The higher the frequency of an electromagnetic wave, the more energy it transfers. Different wavelengths of the spectrum are reflected, absorbed or transmitted differently | -travel through space at 300million m/s |
Grandma's Xbox Uses Volts In My Room Gamma X-rays Ultraviolet Visible light Infrared Microwaves Radio | Gamma has the shortest wavelength and the highest frequency. Radio has the longest wavelength and lowest frequency |
visible light is detected by our eyes see different wavelengths as different colours. The wavelength increases from violet to red. Can be used for photography | IR is emitted by all objects. Used for remote controls for TVs and CDs |
Microwaves are used for communication. Microwave transmitters produce wavelengths that are able to pass through the atmosphere. They send signals to and from satellites and withing mobile phone networks | Radio waves transmit radio and TV programs and carry mobile phone signals |
The radio and microwave spectrum is divided into different bands; which are used for different communication purposes | The shorter the wavelength, the more information they carry. The shorter their range, the less they spread out |
Mobiles communicate with a local mobile phone mast using wavelengths as microwaves/radio waves | Research is needed to evaluate whether or not mobile phones are safe to use(may affect the brain) |
Optical fibres are very thin glass fibres. We use them to transmit signals carried by VL or IR. The signals travel down the fibre by repeated total internal reflection | They're useful in communications because they carry much more information and are more secure than radio waves and microwaves |
Repeated total internal reflection |
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