What is a correct order of the colours in a spectrum of white light?
red→orange→green\text{red} \rightarrow \text{orange} \rightarrow \text{green}red→orange→green
orange→red→green\text{orange} \rightarrow \text{red} \rightarrow \text{green}orange→red→green
green→red→orange\text{green} \rightarrow \text{red} \rightarrow \text{orange}green→red→orange
red→green→orange\text{red} \rightarrow \text{green} \rightarrow \text{orange}red→green→orange
12 exam-style questions on CIE IGCSE Physics 3.2.4 Dispersion of light. Each one has a worked solution and a mark scheme showing where the marks go.