(1)灯泡的电阻为RL= U2 P = (6V)2 6W =6Ω;(2)灯泡的额定电流为IL= P额 U额 = 6W 6V =1A,通过电阻的电流为IR=I-IL=1.5A-1A=0.5A,定值电阻的阻值为R= U IR = 6V 0.5A =12Ω;(3)定值电阻R消耗的电功率为PR=UIR=6V×0.5A=3W.答:灯泡L的电阻值为6Ω;定值电阻R的阻值为12Ω;定值电阻R消耗的电功率为3W.