The figure represents a voltage regulator circuit using a Zener diode. The breakdown voltage of the Zener diode is 6 V and the load resistance is, $\mathrm{R}_{\mathrm{L}}= 4 \mathrm{k} \Omega$. The series resistance of the circuit is $R_{\mathrm{i}}=1 \mathrm{k} \Omega$. If the battery voltage $\mathrm{V}_{\mathrm{B}}$ varies from 8 V to 16 V , what are the minimum and maximum values of the current through Zener diode?