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| Question | Answer |
| Explain the geocentric model | It was thought that everything orbits around the Earth |
| Explain the heliocentric model | It was though that everything orbits around the Sun |
| How was the heliocentric model proved? | Galileo observed Jupiter's moons with his telescope (new invention). He realised that the moons appeared to go the 'wrong way' and got carried along with the planet. This showed that not everything orbits the Sun |
| Explain how the heliocentric model is different to today's model | The current model still states that the planets orbit the Sun, but the orbits are eliptical rather than circular |
| Definition of wavelength | distance from one peak to the next |
| definition of frequency | how many complete waves there are per second (passing a certain point). Measured in Hertz (Hz) |
| definition of amplitude | the height of the wave (from the mid-line to the peak) |
| what do waves transfer | Waves transfer energy and information without transferring matter |
| describe a transverse wave | In transverse waves the vibrations are at 90' to the direction of travel of the wave |
| describe a longitudinal wave | In longitudinal waves the vibrations are along the same direction as the wave is travelling |
| name 2 examples of transverse waves | light + all EM waves |
| name 2 examples of longitudinal waves | sound + ultrasound |
| name the triangle that links speed, frequency and wavelength | v (speed) ----------------------------------- f (frequency) x lambda (wavelength) |
| how do you remember the speed, wavelength, frequency triangle? | Very Fat Ladybird velocity(speed), frequency, lambda(wavelength) |
| what is frequency measured in? | Hertz (Hz) |
| what is wavelength (lambda) measured in? | metres |
| what is speed measured in? | m/s metres/second |
| what is the law of reflection? | angle of incidence=angle of reflection |
| sound waves travel____in ______? | sound waves travel faster in denser substances |
| what happens when a wave crosses a boundary between 2 substances? | when a wave crosses a boundary between 2 substances it changes speed |
| what is a real image? | light from an object comes together to form an image on a screen |
| what is a virtual image? | when light rays are diverging so they look like they are coming from a completely different place |
| what is a converging lens used for? | converging lens - used to focus light |
| what does a converging lens do? | it causes parallel rays of light to converge to a focus |
| EM waves travel_____in ______? | EM waves travel slower in denser media |
| define the focal length | distance from the lens to the focal point |
| explain how a refracting telescope works | 1)the objective lens gathers and bends light into the focal point where a real image is formed 2) the light from the real image enters the eyepiece 3) the rays of light are spread out so they leave magnified |
| explain how a reflecting telescope works | 1) a concave mirror collects the parallel rays and reflects them into a smaller mirror (placed in front of the concave mirror's focal point) 2) the smaller mirror reflects the light into a converging eyepiece (magnifies the image) |
| explain what happens as you go from left to right on the EM spectrum | the waves increase in frequency and decrease in wavelength |
| how do you remember the order of the EM waves? | Ren Made India Violent Using Xtreme Growling |
| who discovered Infrared? | Herschel |
| who discovered UV? | Ritter |
| what do refracting telescopes use? | objective lens + eyepiece lens |
| what do reflecting telescopes use? | mirrors + converging lens |
| explain how infrared was discovered | 1) when white light goes through a prism, it creates a spectrum 2) he used a thermometer to measure the temperature each colour gave out. he noticed that it increased from violet to red 3) he measured passed the red part where there was no visible light and found the hottest temperature - infrared |
| explain how UV was discovered | 1) he carried out experiments to see if he could find anything at the violet end 2) he measured how fast silver chloride turned black when exposed to the different colours 3) he saw the quickest change happen passed the violet end - he had discovered UV |
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