Final answer:
The statement is false because a cross-section usually refers to a two-dimensional representation of a cut through a structure, not the intersection of two lines.
Step-by-step explanation:
The statement 'a cross-section is where two lines come together' is false. A cross-section typically refers to a two-dimensional plane or surface that results from cutting through an object or structure. When creating a cross-section in geological mapping, it is ideal to make this cut perpendicular to contact lines or geological features to accurately represent the true dip of layers or structures. Unlike geological cross-sections, which provide information about layers and contacts within the Earth, in physics and mathematics, a cross-section may represent areas of interest such as the plane of zero potential between charges, or it could show how waves superpose in a given medium.
An example in the context of physics would involve equipotential lines that form closed loops around charges. These aren't necessarily the result of two lines coming together, but rather the representation of points with the same electric potential due to the presence of electrical charges. It is important to distinguish between intersections of lines and cross-sectional representations, which are conceptual cuts through a three-dimensional structure represented in two dimensions.