In that year's senior high school entrance examination, the power supply voltage was 4.5V in the experiment of "measuring the electric power of small bulbs" The rated voltage of the small bulb is 2.5V and the resistance is about 10 Ω

In that year's senior high school entrance examination, the power supply voltage was 4.5V in the experiment of "measuring the electric power of small bulbs" The rated voltage of the small bulb is 2.5V and the resistance is about 10 Ω


In the experiment of measuring the electric power of small light bulb, the power supply voltage is 4.5V, the rated voltage of small light bulb is 2.5V, and the resistance is about 10 Ω. (1) when connecting the circuit, the switch should be disconnected. (2) please use the stroke line instead of the wire to complete the physical circuit in Figure A. (3) before closing the switch, slide the slide P of rheostat



In order to make the "6V & nbsp; 3W" bulb connect to 8V power supply to light normally, what resistance should be connected in series? What is the electrical power consumed by the resistor?


The voltage of the lamp is 6V and the power is 3W when the lamp normally lights up. The total voltage in the series circuit is equal to the sum of the partial voltages. When the lamp normally lights up, the voltage at both ends of the series resistor is ur = u-ul = 8v-6v = 2V. The current in the series circuit is equal. According to P = UI, the current in the circuit is I = plul = 3w6