Final answer:
The slope of the water table is referred to as the hydraulic gradient, which is similar to the steepness shown by contour lines on a topographic map. Equipotential surfaces are perpendicular to field lines and help to visualize changes in potential energy across a region.
Step-by-step explanation:
The slope of the water table is known as the hydraulic gradient. This is similar to isolines on a topographic map, which represent lines of equal gravitational potential energy. Like contour lines which show changes in elevation or steepness of a surface, the hydraulic gradient represents the slope of the groundwater surface. Essentially, as the space between isolines—whether they be for gravitational potential on a topographic map or for electric potential on an electric field map—decreases, the gradient increases, implying a steeper slope.
It is important to note that equipotential surfaces are always perpendicular to field lines, whether they be gravitational or electric. This concept helps us understand how potential energy changes across a region. In the case of groundwater, imagining equipotential lines similar to those on topographic maps can help visualize how water moves underground following the slope or hydraulic gradient.