A beam of light from the Sun strikes a prism.
The dispersed beam is incident on a white wall between X and Y. Which colours are seen at X, Z and Y?
Correct Answer: \( \boxed{\mathrm{C}} \)
White light from the Sun contains all the colours of the visible spectrum. When it passes through a prism, the different colours are refracted by different amounts. This process is called dispersion.
Violet light has the shortest wavelength and highest frequency, so it is refracted the most by the prism.
Red light has the longest wavelength and lowest frequency, so it is refracted the least.
Therefore, on the wall:
\(X =\) violet
\(Z =\) green
\(Y =\) red
The order of colours in the visible spectrum is: \( \mathrm{Red \rightarrow Orange \rightarrow Yellow \rightarrow Green \rightarrow Blue \rightarrow Indigo \rightarrow Violet} \).
Thus, the arrangement \(X=\) violet, \(Z=\) green, and \(Y=\) red corresponds to Option C.
White light can be split into different colours by passing it through a prism.
What is the name of this process?
Correct Answer: \( \boxed{\mathrm{B}} \)
When white light passes through a prism, each colour is refracted by a different amount because different wavelengths travel at different speeds in glass.
Violet light is refracted the most, while red light is refracted the least. As a result, the white light separates into its constituent colours, forming a visible spectrum.
This splitting of white light into its component colours is called dispersion.
Diffraction refers to the spreading of waves around obstacles or through gaps, reflection is the bouncing of light from a surface, and total internal reflection occurs when light is completely reflected within a denser medium.
Therefore, the correct answer is (B) dispersion.
Which list shows the colours present in the visible spectrum in order of increasing wavelength?
Correct Answer: \( \boxed{\mathrm{A}} \)
The colours of the visible spectrum are arranged in order of increasing wavelength as:
\( \mathrm{Violet \rightarrow Indigo \rightarrow Blue \rightarrow Green \rightarrow Yellow \rightarrow Orange \rightarrow Red} \)
Violet light has the shortest wavelength and the highest frequency, while red light has the longest wavelength and the lowest frequency.
Considering only the colours listed in the options, the correct order of increasing wavelength is:
\( \mathrm{Green \rightarrow Yellow \rightarrow Orange \rightarrow Red} \)
Therefore, Option A follows the correct progression from shorter wavelength to longer wavelength.
Hence, the correct answer is (A).
