[填空题]
A flash lightbulb rated at 2.5 W and nry((pj2y.s t9cgi6m,ho;h d 3.0 V is operated by a 9.0-V b/l i 3aix m m2p;9mqv1.x,pn2ke0 erlzattery. To light the bulb at its rated voltage and power, a resistor R is connected in series as shown in (Fig. Below). What value should the resisti;0/ex9x vlak m2 ir.zmm3 e,12plnpqor have? $\Omega$
