Topic 5 - Light and the Electromagnetic Spectrum Flashcards
SP5a - What two processes can be shown using a ray diagram?
- Reflection
- Refraction
SP5a - What do i and r represent in ray diagrams?
- i: Angle of incidence (between incident ray and the normal)
- r: Angle of reflection/refraction (between reflected/refracted ray and the normal)
SP5a - What is the relation between the angles of incidence and reflection/refraction?
i = r (Angle of incidence = angle of reflection/refraction)
This is the law of reflection
SP5a - What is the normal?
The line drawn perpendicular to the object light is reflecting off (or refracting through)
SP5a - Describe total internal reflection.
- TIR occurs when light refracts through a substance at sucha low angle of incidence that it doesn’t leave the other side
- This angle is called the critical
- If light enters at the critical, it will move along the interface
- If light enters at an angle smaller than the critical, it will cause TIR to happen
SP5a CP - Describe a method to explore refraction with varying angles of incidence,
- Place a ray box with a slit in front of it on a piece of paper
- Place a glass box the way of the ray of light thta is being produced
- Draw around the glass block
- Mark the point of entry and exit for the light aswell as two further points (such as origin and edge of paper) on the piece of paper
- Use your markings to draw lines representing the travel of the ray of light
- Repeat with ray box at different angles and compare your results
SP5b - What are the two types of reflection?
- Specular: When light is reflected evenly on a smooth surface
- Diffuse: When light is reflected in all directions on a rough surface
SP5b - Describe why a green object appears green in sunlight.
- Sunlight is made up of white light as it contains all the colours of the visible spectrum
- An object that appears green will reflect the green part of the spectrum but reflect all the other colours
SP5b - what effect would a blue filter have?
A blue filter would only transmit the blue part of the light that goes to it.
SP5d - What are the similarities between all EM waves?
- They are all transverse waves
- They all travel at (3x10^8m/s) ina vacuum
- They transfer energy
SP5d - How were infrared waves discovered?
- A prism was used to refract white light into the seven componenets.
- A thermometer was placed just outside of the red part of this spectrum.
- Another was placed in the spectrum.
- The thermometer next to red was warmer suggesting there was something warming it up
SP5e - List all the colours in the visible light spectrum.
ROYGBIV
- Red
- Orange
- Yellow
- Green
- Blue
- Indigo
- Violet
SP5e - List all of the EM waves in order of increasing wavelength/decreasing frequency.
- Gamma rays
- X-rays
- Ultraviolet
- Visible light
- Infrared
- Microwaves
- Radio waves
SP5e - Why do different telescopes need to be used to study different EM waves?
EM waves of different length get absorbed by different amounts by the atmosphere
SP5f - What can infrared be used for?
- Heating food
- Short range communication such as TV remotes
- Security systems
SP5f - What can microwaves be used for?
- Communications and satellite transmissions
- Heating up food and giving it energy