The induced electromotive force (emf) or voltage ($\varepsilon$) across an inductor is proportional to the rate of change of current with respect to time. The relationship is given by the formula: $\varepsilon = -L \frac{dI}{dt}$ Where $L$ is the self-inductance .

Analysis of the Graphs:

1. Slope Relationship: The voltage graph corresponds to the negative derivative of the current graph ($-\text{slope of } I \text{ vs } t$).
2. Linear Change: If the current $I$ changes linearly with time (constant slope), the induced voltage $\varepsilon$ will be constant (a horizontal line). If $I$ increases linearly (positive slope), $\frac{dI}{dt}$ is positive, so $\varepsilon$ is negative (constant). If $I$ decreases linearly (negative slope), $\frac{dI}{dt}$ is negative, so $\varepsilon$ is positive (constant).
3. Zero Change: If $I$ is constant (zero slope), $\frac{dI}{dt} = 0$, and thus $\varepsilon = 0$.

Note: Without the specific visual of the $I-t$ plot, the exact shape of the answer cannot be drawn, but it will follow these mathematical rules (e.g., a triangular current wave produces a square voltage wave).