Year 8 Light Flashcards
What are the three secondary colours of light and what are they made of?
Cyan - blue and green, magenta - red and blue, yellow - green and red
How do coloured surfaces work?
They reflect light of the colour they are and absorb all the other colours
What is reflected if you shine white light onto a red surface?
Red
Is this lens convex or concave? \_\_\_\_\_ \ / | | / \ \_\_\_\_\_
Concave
What is reflected if you shine white light onto a yellow surface?
Red and green
What are the colours of the spectrum of light?
Red, Orange, Yellow, Green, Blue, Indigo, Violet
What is reflected if you shine green light onto a red surface?
Nothing - you see the object as black
How do old 3D images work?
On one eye you wear a red lens and on the other a blue one. The images uses lots of red and blue lines. On the eye with the blue lens you cannot see any of the red on the image, and vice versa for the other eye. This tricks your brain into thinking you are seeing a 3D image, as you are seeing two images
What are the three primary colours of light?
Red, green and blue
What do you get if you mix all the colours of light?
White
What does a diverging lens do?
Spreads light
How does refraction work?
When light enters a denser material at an angle the side of the beam of light that hits it first slows down first, as it is hitting more particles, while the other side remains the same speed. This makes it change direction
What is reflected if you shine red light onto a yellow surface?
Red
Fill in the gaps: When light enters a denser material it bends ________ the normal. When light exits a denser material into a less dense one it bends ________ the normal.
- Towards
2. Away from
Are converging lenses convex or concave?
Convex
What is the normal?
An imaginary line at 90º from an object
What does a converging lens do?
Focuses light
Are diverging lenses convex or concave?
Concave
What is wrong with shortsighted people and how can it be fixed?
Their eyes focus the light too late - after the retina. It can be fixed with a convex lens
Where should the image in your eye be focussed on?
The retina
What is the point where the rays of light come together called?
The focal point
What is it called when white light is split up into the spectrum?
Dispersion
Who discovered infrared?
Herschel
How was infrared discovered?
Herschel measured the temperature of different parts of the spectrum of light and found that red and colours by it were much hotter than blue and colours by it. He then measured just past red and found it to be even hotter
Where is infrared on the electromagnetic spectrum?
Just below red, a part of visible light
Who discovered ultraviolet?
Ritter
How was ultraviolet discovered?
Ritter used silver chloride, a chemical that blackens in sunlight, on different parts of the spectrum. It discoloured very slowly in red light, but much quicker in violet light. He tried just past violet and found it discoloured even quicker.
