Second part, i couldn't post more. I should be another 20 minutes.
Took longer than expected as i was busy.
You're exam board is ocr right? So i'm on a different exam board and the syllabus is different. Some of this from general knowledge. This thread is about core science so i'm willing to help with any enquires linked to the course XD
Explain how microwave and infrared radiation transfers energy to materials.
Microwaves penetrate up to 1cm into food. Microwaves penetrate through glass and plastic but are reflected by shiny metal surfaces. Special glass in a microwave oven door reflects the microwaves.
Microwaves cook food bu microwave radiation. The water and fat molecules in the outer layers of the food absorb the microwave radiation and vibrate more, energy is subsequently transferred to the inner layers of the food conduction.
Normal ovens cook food bu infrared radiation. Energy is absorbed by the surface food particles and is transferred to the inner layers by conduction as the particles gain more kinetic energy.
Describe how energy associated with microwaves and infrared depends on their frequency.
High frequency waves transfer more energy .
Recall the energy of microwaves and infrared to their potential dangers.
Microwaves cannot be seen as their wavelengths are too long. They burn tissue as the water molecules absorb the radiation, this can lead to cancer. They have shorter wavelengths than the microwaves used for mobile phones and thus cause more damage.
Infrared radiation causes to skin.
Explain how microwave signal loss happens.
In the use of microwaves in communication, the transmitter and receiver must be in line of sight.
Microwaves do not show much diffraction, so sometimes cannot diffract around buildings. The natural curvature of the earth limits the line of sight and adverse weather cinditions scatter signals.
Explain how signal loss problems can be reduced
Signal loss can reduced situating aerials on top of high buildings. Satelites are in line of sight as there are no obstructions in space. Large aerials can handle thousands of signals at once.
Explain how a remote control
Pressing a button on a remote control
A coded signal is sent to a light emitting diode (LED) at the front of the remote. The signal includes a start command, the instruction command, a device code and a stop command
The LED then transmitts a series of pulses which are received and decoded by the device, so that it can complete a function. Like changing volume or channel.
Describe the advantages of digital signals
Digital signaks can use multiplexing, which enables large numbers of signals to be transmitted simultaneously.
Inteference isn't apparent on digital signals, as digital signals only have two values.
Describe the advantages of optical fibres
Optical fibres allow data to be transmitted faster than microwaved and radiowaves, visible light has a higher frequency, optical fibres still work when bent, whereas normal wires don't.