Question

Which of the following is not a primary colour?A. YellowB. RedC. GreenD. Blue

Hint: Primary colours are the set of colours that can not be obtained by mixing two or three colours. These colours are used to obtain different colours Using this principle and considering each colour we will find which colour is not a primary colour.

First of all, we will consider that primary colours can not be obtained by mixing any two colours. They are used to obtain different colours.

Now, we will consider the option (a) i.e. Yellow, we know that yellow colour can not be obtained by combining any of the colours but using yellow colour we can make different colours such as, orange, green etcetera.

Now, considering the option (b) i.e. Red, we know that red colour cannot be obtained by combining any of the colours but using red colour we can make many different colours such as, orange, brown etcetera.

Considering option (c) i.e. Green, we know that green colour is made by combining yellow and blue. So, it is not a primary colour, it can be considered as a secondary colour.

Now, considering the option (d) i.e. Blue, we know that blue colour cannot be obtained by combining any of the colours but using red colour we can make many different colours such as, green, brown etcetera.
Hence, we can say that Green is not a primary colour.

So, the correct answer is “Option C”.

Note:
This problem can also be solved by doing the experiment of incidenting different lights on a mirror and then observing the reflection on a paper but that cannot be done each and every time so students must know the basics of primary, secondary and tertiary colours.