Question

On which axis is a dependent and independent variable placed?

Answer 1

Usually the independent variable is the x-variable and the dependent variable is the y-variable

Answer 2

y-axis=Dependent
x-axis=Independent

Answer 3

As JamesJ said, usually. It's not strictly a requirement, but general convention places it as such, having y = (something in terms of x). Sometimes it's more convenient to swap them around though, having the independent variable on the y-axis; it just depends what you're trying to graph.