Light is everywhere around us, but have you ever wondered...
Combined Science133 views·Updated 10 Jul 2026·2 pagesOrganizador de Conocimientos de Física - La Luz
Olamide@olamide_26
1
of 2
Light Basics and Behaviour
Ever noticed how you can't see anything in a completely dark room? That's because most objects are non-luminous - they don't produce their own light. You only see them because they reflect light from luminous objects like the sun or a lamp into your eyes.
Light travels in straight lines at an incredible speed of 300,000 km/s through space. It can pass through transparent materials like glass, translucent ones like frosted glass (though it gets scattered), but stops completely at opaque materials like walls.
When light hits a smooth surface like a mirror, it creates specular reflection - this is why you see a clear image. The law of reflection states that the angle of incidence equals the angle of reflection. Rough surfaces cause diffuse scattering, spreading light in all directions.
Quick Tip: Remember that light always reflects off surfaces at the same angle it hits them - just like a ball bouncing off a wall!
Refraction happens when light changes direction as it moves between different materials. That bent-looking pencil in water? Light slows down in water and bends towards the normal line, then speeds up and bends away when it exits back into air.
2
of 2
How We See: Eyes, Cameras and Colour
Your eye works like a brilliant natural camera. Light enters through the pupil (controlled by the iris muscle), gets focused by the cornea and lens onto the retina. The retina contains photoreceptors - rods for movement and dim light, cones for colour and bright light.
Modern cameras work similarly to your eyes. Light passes through an opening onto pixels (photosensitive picture elements) that convert light into electrical charges. Both eyes and cameras create real, inverted images that get flipped the right way by your brain or camera software.
White light contains all colours of the rainbow. A prism can split white light into its spectrum through dispersion - this happens because different colours refract by different amounts. Red bends least, violet bends most.
Colour Rule: Objects appear coloured because they reflect certain colours and absorb others - a red apple reflects red light but absorbs all other colours.
Filters work by absorbing certain colours whilst letting others through. This is why a red object looks black under blue light - there's no red light to reflect back to your eyes!
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Combined Science133 views·Updated 10 Jul 2026·2 pagesOrganizador de Conocimientos de Física - La Luz
Olamide@olamide_26
Light is everywhere around us, but have you ever wondered why you can see yourself in a mirror or why a pencil looks bent in water? Understanding how light behaves helps explain everything from how your eyes work to why...
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Light Basics and Behaviour
Ever noticed how you can't see anything in a completely dark room? That's because most objects are non-luminous - they don't produce their own light. You only see them because they reflect light from luminous objects like the sun or a lamp into your eyes.
Light travels in straight lines at an incredible speed of 300,000 km/s through space. It can pass through transparent materials like glass, translucent ones like frosted glass (though it gets scattered), but stops completely at opaque materials like walls.
When light hits a smooth surface like a mirror, it creates specular reflection - this is why you see a clear image. The law of reflection states that the angle of incidence equals the angle of reflection. Rough surfaces cause diffuse scattering, spreading light in all directions.
Quick Tip: Remember that light always reflects off surfaces at the same angle it hits them - just like a ball bouncing off a wall!
Refraction happens when light changes direction as it moves between different materials. That bent-looking pencil in water? Light slows down in water and bends towards the normal line, then speeds up and bends away when it exits back into air.
2
of 2Sign up to see the content. It's free!
- Access to all documents
- Improve your grades
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By signing up you accept Terms of Service and Privacy Policy
How We See: Eyes, Cameras and Colour
Your eye works like a brilliant natural camera. Light enters through the pupil (controlled by the iris muscle), gets focused by the cornea and lens onto the retina. The retina contains photoreceptors - rods for movement and dim light, cones for colour and bright light.
Modern cameras work similarly to your eyes. Light passes through an opening onto pixels (photosensitive picture elements) that convert light into electrical charges. Both eyes and cameras create real, inverted images that get flipped the right way by your brain or camera software.
White light contains all colours of the rainbow. A prism can split white light into its spectrum through dispersion - this happens because different colours refract by different amounts. Red bends least, violet bends most.
Colour Rule: Objects appear coloured because they reflect certain colours and absorb others - a red apple reflects red light but absorbs all other colours.
Filters work by absorbing certain colours whilst letting others through. This is why a red object looks black under blue light - there's no red light to reflect back to your eyes!
We thought you’d never ask...
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
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Students love us — and so will you.
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