Pleas ehelp about convergent boundaries and don't spam I really need help on a few question PLZZZ

Tungsten-filament lightbulb emits light based on the temperature of the filament. which phenomenon does this demonstrate?

Why is the energy that results from a roller coaster's position at the top of a hill referred to as potential energy?

Give one example to show that when substances are mixed, it may result in a chemical or a physical change depending on the conditions.