Primary colours of light are

Analysis

The question asks for the primary colours of light. In physics, specifically in the study of optics, primary colours are defined as the set of colours that can be combined in different intensities to produce a broad range of other colours.

Explanation

• Primary Colours of Light (Additive Mixing): When we talk about light (as opposed to pigments or paints), the primary colours are Red, Green, and Blue (RGB). When these three colours are mixed together in equal intensity, they produce white light. This is the principle used in television screens, computer monitors, and smartphone displays.
• Secondary Colours: When you mix two primary colours of light, you get secondary colours: • Red + Green = Yellow • Green + Blue = Cyan • Blue + Red = Magenta
• Distinction: Do not confuse these with the primary colours of pigments (subtractive mixing), which are Cyan, Magenta, and Yellow (CMY), often used in printing.

Step-by-Step Solution

1. Identify the context: The question specifically asks for the primary colours of light.
2. Recall the additive colour theory: The fundamental colours that cannot be created by mixing other colours of light are Red, Green, and Blue.
3. Evaluate the options: • Option A: Red, blue, and green (Matches the additive primary colours). • Option B: Cyan, magenta, and yellow (These are secondary colours of light or primary colours of pigments). • Option C: Black is the absence of light, so it cannot be a primary colour. • Option D: Incorrect, as Option A is valid.

Conclusion

The primary colours of light are Red, Green, and Blue. Therefore, Option A is the correct answer.

Exam Tip

To remember this easily, think of the acronym RGB. Just remember that your phone screen (which emits light) uses RGB pixels to create every image you see!