Physics Tutorials

Colours


Each colour you can think of is just a combination of three colours. They are called primary colours. The three primary colours are:

    1) Red
    2) Green
    3) Blue

The following programme lets you make any colour you can think of by mixing the three primary colours in various proportions. You can enter the values for Red, Green and Blue - a number less than 255 - and make various colours. That is how modern computers produce millions of colours using the three primary colours. Thanks to this little programme, you can have some fun too.


RedGreenBlue



Here are some exciting values for you to play with:

RedGreenBlueColour
1654242Brown
23716461Crimson
00139Dark Blue
13900Dark Red
01000Dark Green
2552150Gold
750130Indigo
2550255Magenta
2551650Orange
2552550Yellow
0128128Teal
0255255Cyan
1608245Sienna
1281280Olive
128128128Grey

White Light


White light, consists of seven colours: red, orange, yellow, green, blue, indigo, violet. The acronym - Richard Of York Gave Battle In Vain - sums up that all. The visible spectrum of sunlight consists of these seven colours.


Filters


A colour filter lets its own colour through while absorbing the rest. The following animations shows colour filtering.


filtering

filtering

Watch the way only the colours of the filters are allowed to go through.


Reflection of Light by paints


The colour of the paint is reflected when white light hits a paint. The following animations show that.


filtering

filtering

The colour of the paint is taken away from the white light and then reflected. The rest of the colours are absorbed.

Please answer the following questions.


    1) A beam of white light falls on a red filter. Which colour will emerge from the filter?
    2) A beam of yellow light falls on a red filter. Which colour will emerge from the filter?
    3) A beam of yellow light falls on a blue filter. What is the outcome?
    4) A beam of yellow light, first falls on a red filter and then on a green one. What will you see?
    5) A beam of yellow light falls on a yellow filter at first, then a green filter. What will you see?
    6) A beam of white light hits a red surface and then goes through a green filter. What will you see?
    7) A beam of red light hits a green surface. What will happen?