Flashcards
Physics topic 6
Cards in this deck (34)
- 1Experiments with wavesPages 128/129
- 2How waves are absorbed transmitted and reflectedThe waves are absorbed by the material the wave is trying to cross into- transferring energy to the materials energy stores.
Waves are transmitted- they carry on travelling through the new material often leading to refraction
Waves are reflected - 3Rule for all reflected wavesAngle of incidence= angle of reflection
- 4What is the angle of incidenceThe angle between the incoming wave and the normal
- 5What is the angle of reflectionThe angle between the reflected wave and the normal
- 6What is the normalAn imaginary line that’s perpendicular to the surface at the point of incidence
- 7What is specular reflectionHappens when a wave is reflected in a single direction by a smooth surface
- 8What is diffuse reflectionWhen a wave is reflected by a rough surface and the reflected rays are scattered in lots of different directions
Happens because the normal is different for each incoming Ray which means the angle of incidence is different for each Ray.
When light is reflected by rough surface the surface appears matte and you don’t get clear reflection - 9What is refractionWhen a wave crosses a boundary between materials at an angle and it changes direction
How much it is refracted depends on how much wave speeds up/ slows down which depends on density of materials- higher the density the slower the wave travels through it
If wave crosses boundary it slows down and bends towards the normal.
If wave crosses into a material it speeds up and bends away from normal
Wavelength changes when refracted
Frequency of wave stays the same when refracted - 10Ray diagram -Page 131
- 11Investigating lightPage 132/133
- 12Wave spectrumRadio waves
Microwaves
Infrared
Visible light
Ultra violet
X-rays
Gamma rays
Increasing frequency and decreasing wavelength ⬇️⬇️⬇️ - 13Oscillating chargesPage 136
- 14Uses of radio wavesLong wave radio waves- radio signals
Short wave radio signals- Bluetooth
Medium wave signals- tv and fm radio - 15Uses for microwavesSatellites
Microwave ovens- use different wavelengths than satellites as they need to be absorbed - 16Uses for infrared wavesInfrared cameras- using infrared radiation to monitor temperature
Electric heaters- emit infrared radiation to increase heat - 17Uses of visible lightOptic fibres- carry data as pulses or visible light
- 18Uses of ultraviolet wavesFluorescent lights- generate UV , which is absorbed and re emitted as visible light.
Security pens- under UV the ink is fluorescent otherwise invisible
Tan- UV sun rays - 19Uses of X-rays and gamma raysRadiographer- see broken bones and treat radiotherapy.
- 20Dangers of electromagnetic radiationLow frequency waves (e.g. radio waves)- can pass trough soft tissue without being absorbed
High frequency transfer lots of energy and cause lots of damage:
UV- damages surface cells leading to sunburn and cause skin cancer
X-ray and gamma- ionising radiation so they can carry enough energy to knock electrons off atoms- causing gene mutation or cell destruction - 21Sieverts and measuring riskPage 140
- 22Convex lensesBulge outwards
Cause rays of light parallel to axis to converge at principal focus
Principle focus = where rays hitting the lens parallel to axis all meet - 23Concave lensCaves inwards
Causes rays of light parallel to axis to diverge
Principal focus = where rays hitting lens parallel to axis appear to all come from - 24Axis of a lens=Line passing through middle of lens
- 25Focal length=The distance from centre of lens to principal focus
- 26Three rules for refraction in convex lens1) an incident ray parallel to axis refracts through the lens and passes through the principal focus on the other side
2) an incident tag passing through the principal focus refracts through the lens and travels parallel to axis
3) an incident ray passing through centre of lens carries on in the same direction - 27Three rules for refraction in concave lens1) an incident ray parallel to the axis refracts through the lens and travels in line with principal focus
2) an incident ray passing through the lens towards the principal focus refracts through the lens and travels parallel to the axis
3) an incident ray passing through the centre of lens carries on in the same direction - 28Inside the earthEarths crust- solid layer of rock about 50km thick that surrounds the mantle
Mantle- thicker layer of molten rock
Beneath the mantle is inner core and outer core - 29What is an earthquakes focusThe point where an earthquake originates from
- 30Types of seismic wavesPrimary waves- cause the initial tremors lasting about one minute. These are longitudinal waves that push/ pull on material as they move through the earth
Secondary waves- cause more tremors a few minutes later. Transverse waves that travel more slowly than primary. Shake the material they pass through inside the earth from side to side
Long waves- arrive last and cause violent movements on the surface up and down as well as backwards and forwards. Travel more slowly than primary and secondary and only happen in earths crust - 31Way the different waves move through earthPrimary and secondary waves bend as they travel through the mantle. Because their speed changes gradually with depth and so their direction changes with depth
Primary waves refract at the boundary between the mantle and outer core
Secondary waves are transverse so they can’t travel through liquid outer core - 32Transparent objectsTransmit all the incident light that enters the object. No light is absorbed at its surface. Light travels through the object.
- 33Translucent objectLet light pass through them but the light is scattered or refracted. Happens because the material of the object has lots of internal boundaries that change the direction of the light rays repeatedly.
You can see light but not images - 34Opaque objectsObject that absorbs all the light that reaches it. The light is either reflected, scattered at the surface, or absorbed by the object
No light travels all the way through so nothing can be seen through
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- Flashcards on Physics topic 6, created by phoebe Garr on 18/06/2018.
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