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22 Dec 2025

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2 pages

Understanding Visible Light and Colors

Inyiego Coheh

@yumify

Ever wondered why objects appear different colours or how sunglasses... Show more

# Visible Light and Colour
Visible Light is made up of a spectrum of colours ranging from red to violet: with red having the
longest wavelen

Understanding Visible Light and Colour

Visible light isn't just one thing - it's actually made up of a whole spectrum of colours that your eyes can detect. Think of it like a rainbow: red light has the longest wavelength and lowest frequency, whilst violet has the shortest wavelength and highest frequency.

The colours in order are red, orange, yellow, green, blue, indigo, and violet (remember "Roy G. Biv"!). White light is actually all these colours combined together, whilst black is simply the absence of light altogether.

The colour you see when looking at any object depends on two main factors: what light is hitting it and the object's properties. These work together to determine which light gets absorbed, reflected, or transmitted through the object.

Key Insight: The colour you see isn't actually "in" the object - it's the light bouncing off it that creates the colour in your brain!

Opaque objects (like a brick wall) don't let any light pass through them. Instead, they absorb some colours and reflect others back to your eyes. A blue football looks blue because it reflects blue light whilst absorbing all the other colours.

How Transparent Objects and Filters Work

Transparent objects like clear glass let almost all light pass through them, whilst translucent objects like frosted glass only let some light through. The colour of translucent objects depends on which wavelengths they transmit most - a green bottle looks green because it lets more green light through than other colours.

Colour filters are brilliant tools that work by blocking certain colours whilst letting others pass through. Primary colour filters (red, green, or blue) only allow one of these three colours through and absorb everything else.

Here's where it gets interesting: if you shine white light through a green filter, only green light comes out the other side. But if you looked at a blue object through that same green filter, the object would appear black because the filter blocks the blue light completely.

Pro Tip: Non-primary filters like yellow work differently - they let through multiple wavelengths that combine to create that colour $red + green = yellow$ .

This is exactly how your sunglasses work, and why photographers use different coloured filters to create specific effects in their photos.

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Physics

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114

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22 Dec 2025

•

2 pages

Understanding Visible Light and Colors

Inyiego Coheh

@yumify

Ever wondered why objects appear different colours or how sunglasses work? It's all about visible light and how it interacts with different materials. Understanding this will help you grasp everything from why the sky looks blue to how your phone... Show more

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Understanding Visible Light and Colour

Key Insight: The colour you see isn't actually "in" the object - it's the light bouncing off it that creates the colour in your brain!

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Access to all documents

Improve your grades

Join milions of students

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How Transparent Objects and Filters Work

Pro Tip: Non-primary filters like yellow work differently - they let through multiple wavelengths that combine to create that colour $red + green = yellow$ .

This is exactly how your sunglasses work, and why photographers use different coloured filters to create specific effects in their photos.