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| Frage | Antworten |
| Define the term "wave motion" | The transfer of energy without transferring matter |
| Define "transverse wave" | A wave in which its particles vibrate at right angles to the direction of motion of the wave |
| Define "longitudinal wave" | A wave in which the vibration is in the same direction that the wave is travelling |
| Define "frequency" | The number of waves produced per second, measured in Hertz (Hz) |
| Define "wavelength" | The distance between successive wave crests, measured in meters |
| Define "electromagnetic radiation" | A range of electromagnetic waves consisting of oscillating electric and magnetic fields travelling at the speed of light |
| Define "electromagnetic waves" | Transverse electric and magnetic fields positioned at right angles to each other, and travelling through empty space at the speed of light |
| Define "electromagnetic spectrum" | The entire range of frequencies of electromagnetic radiation |
| What are two sources of white light? | The sun, and a light globe |
| What colours does white light contain of? | Red, orange, yellow, green, blue, and violet. |
| Why are red, green, and blue primary colours? | Because together, they can form every other colour, and cannot be formed from other colours. |
| When white light is shone upon a magenta filter, what colours pass through? | Red and blue |
| Define the term "refraction" | The term refraction refers to light which has been bent, deflected, or altered. |
| List the electromagnetic spectrum, from shortest to longest wavelength. | Gamma rays, X-Rays, UV light, Visible light, Infrared light, Microwaves, and Radio waves. |
| What is the unit used to measure frequency? | Hertz (Hz) |
| What effect causes skies to be blue? | Skies are blue, due to the shorter wavelength blue light being scattered across the sky more easily than other colours of light. |
| How do you know that white light consists of different colours? | White light consists of different colours, as when all of the colours in the visible spectrum are combined, they all form white lights. These different colours (red, orange, yellow, green, blue, violet), all form white light when combined. Additionally, when white light is shone upon a prism, it is dispersed, and displays all of the different colours. |
| Why does a red surface look red when white light is falling on it? | A red surface looks red when white light is falling on it, as the surface is reflecting the colour red. The white light consists of everything in the visible spectrum (red, orange, yellow, green, blue and violet), and when it is shone upon a surface, the surface reflects and absorbs certain colours. In this case, the surface absorbs the colours orange, yellow, green, blue, and violet, and reflects the colour red, thus giving the surface a red colour. |
| Why is it so difficult to identify a car by its colour at night? | It is quite difficult to identify a car by its colour at night, as during the day, the sun is shining on the cars. This means that the car is exposed to a direct source of light, so it can easily absorb certain colours, and reflect its own. During the night however, the car is not exposed to such a bright direct source of light, so it cannot reflect its own colour, thus making it difficult to identify. |
| Outline the main differences between a transverse wave and a longitudinal wave. | The particles in transverse waves vibrate at right angles to the direction of motion of the waves, whereas the particles in a longitudinal wave vibrate backwards and forwards in the same direction as that of the wave motion. |
| Where can gamma rays be used? | It can be used in chemotherapy/cancer treatment |
| Where can X-Rays be used? | It can be used in hospitals as a way to see through flesh |
| Where can UV rays be used? | They can be used in tanning beds, and are emitted from the sun |
| What is visible light? | The light that we see from the sun |
| Where can infrared light be used? | It can be used by many security cameras, as it picks up on body heat and changing temperatures |
| Where can microwaves be used? | They can be used in microwaves to heat up and cook food |
| Where can radio waves be used? | They can be used by cell phones, radio stations, etc; |
| Define the term "visible spectrum" | The term visible spectrum refers to the range of colours which can be seen by the eye |
| Define "dispersion" | The splitting of white light into different colours |
| What colour has the longest wavelength? | Red |
| What colour has the shortest wavelength? | Violet |
| What are the primary colours? | Red, green, and blue |
| What are the secondary colours? | Cyan, yellow, and magenta |
| What is a colour filter? | A transparent material that allows light of a particular colour to pass through |
| What are the three subtractive primary colours? | Cyan, yellow, and magenta |
| When cyan and magenta paint/ink are mixed, what colour does it make? | Blue |
| When cyan and yellow paint/ink are mixed, what colour does it make? | Green |
| When yellow and magenta paint/ink are mixed, what colour does it make? | Red |
| When red and green light are mixed, what colour does it make? | Yellow |
| When red and blue light are mixed, what colour does it make? | Magenta |
| When blue and green light are mixed, what colour does it make? | Cyan |
| What are gamma rays? | Gamma rays are a form of extremely high-energy electromagnetic radiation, which is emitted from radioactive materials. |
| What are X-Rays? | X-Rays are a form of high-energy electromagnetic radiation, which can penetrate many materials, including human flesh. |
| What are Ultraviolet (UV) rays? | UV rays are a band of electromagnetic radiation, which energies just above those of visible light. It is found in sunlight. |
| What is visible light? | Visible light is a band of electromagnetic radiation, which can be detected by our eyes. |
| What is infrared radiation/rays? | Infrared rays are a band of the electromagnetic spectrum, which energies just below that of visible light. It can be detected by our skin, as heat. |
| What are microwaves? | Microwaves are used in radar and communication systems, whilst shorter microwaves are used in the process of cooking/heating food. |
| What are radio waves? | Radio waves are a form of electromagnetic radiation, with wavelengths ranging from hundreds of metres, to tens of centimetres. It is used in communication. |
| Define the term "analogue signal" | The term analogue signal, refers to a continuous signal that varies in amplitude or frequency, with the information being transmitted. |
| Define the term "digital signal" | The term digital signal refers to a discrete signal consisting of a series of "on" or "off" pulses. |
| What does "remote sensing" mean? | The gathering of information regarding am object or event, without direct physical contact. |
| What does "active remote sensing" mean? | Detecting the reflection or emission of radiation (such as microwaves), that was directed onto a target. |
| What does the term "passive remote sensing" mean? | Detecting the reflection or emission of naturally occurring electromagnetic radiation from a target. |
| What does FDM stand for? | Frequency Division Multiplexing |
| What is FDM (frequency division multiplexing)? | The transmission of several signals along a single channel, using different frequencies. |
| What does TDM stand for? | Time Division Multiplexing |
| What is TDM (time division multiplexing)? | The transmission of several broken and interwoven signals along a channel using a single frequency. |
| Define the term "bandwidth" | The term bandwidth refers to the amount of data that can be transmitted through a communication channel. |
| What is an "optical fibre"? | An optical fibre is a narrow tube of glass or plastic which is used to transmit pulses of light. |
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