To determine the slope of a graph where 'm' is plotted as the abscissa (x-axis) and 'V' is plotted as the ordinate (y-axis).

The abscissa is the x-axis, so 'm' is on the x-axis.
The ordinate is the y-axis, so 'V' is on the y-axis.

The slope ($k$) of a straight line passing through two points $(x_1, y_1)$ and $(x_2, y_2)$ is given by:

In this case, $x$ corresponds to 'm' and $y$ corresponds to 'V'. So, if you select two points from your graph, $(m_1, V_1)$ and $(m_2, V_2)$, the slope will be:

To determine the slope, you would select two distinct points on the straight line of your graph, read their corresponding 'm' and 'V' values, and substitute them into this formula.

Since no graph or data points are provided, a numerical value for the slope cannot be calculated. The method to determine the slope is as described above.