Q. Why is the sun yellow?
A. Stars make light from nuclear fusion reactions of hydrogen into helium. Stars with more hydrogen fuel are very hot and blue in colour. Stars such as our sun are of a medium temperature (only 6000 °C on the surface) and are yellow. Cooler stars are red.
Q. Are all stars like our sun?
A. No. Unlike the sun, 70% of all stars are double stars. Many blue stars are much hotter than our yellow sun, and many red stars are much cooler than our sun.