A 10V Zener diode ( (V_Z = 10V) , (I_Z,min = 1mA) , (I_Z,max = 50mA) ) is used with a series resistor (R = 500\Omega) and an input voltage (V_in = 15V). The load (R_L) draws current (I_L). Find the range of (I_L) for which the Zener maintains regulation.