According to the nameplate of the bulb, the rated voltage of the bulb is 6V, and the bulb can emit light normally. According to the circuit diagram 1, the power supply voltage is U = UL = 6V.
The current when the light bulb normally glows IL Red =PL Red UL Red =3W6V=0.5A, IL Green =PL Green UL Green =6W6V= 1A, and the ammeter indicates:
I=IL red +IL green = 0.5a+1a =1.5a;
(2) The equivalent circuit diagram when switches S and S2 are closed and S 1 is off is shown in Figure 2, which shows the resistance of the green light.
RL Green =U2L Green PL Green =(6V)26W = 6ω. At this time, the total resistance of the circuit is R = UI = 6V0.25A = 24Ω.
The resistance of the sliding rheostat connected to the circuit is r = r-rlgreen = 24Ω-6Ω =18Ω;
So the answer is:1.5; 18.