The Current in A $7.50-\mathrm{H}$ Inductor Is Given By $i=1.8 t^{2}-6.2 t$

The current in a $7.50-\mathrm{H}$ inductor is given by $i=1.8 t^{2}-6.2 t$ . Find the voltage across the inductor at $2.75 \mathrm{~s}$ .