There is a light bulb 2.5V, 0.5A connected to 6V power supply Couplet The ohm resistance is normal

There is a light bulb 2.5V, 0.5A connected to 6V power supply Couplet The ohm resistance is normal

Required string (6-2.5) / 0.5 = ou

When a small light bulb is normally emitting, the voltage and resistance at both ends of the filament are 2.5V and 10 Ω respectively

For a 2.5v10 Ω bulb, its working current is I = u / r = 0.25A. If the power supply is 5.5V, a partial resistance is connected, and the partial voltage at both ends is 3V. According to Ohm's law, r = u / I = 3 / 0.25 = 12 Ω
Therefore, we need to connect a 12 Ω divider to work normally

There is a light bulb, its normal lighting filament resistance is 8.3 Ω, the normal lighting voltage is 2.5 V, if we have only 6 V power supply
How large a resistor should be connected to make a small light bulb shine normally? Listen to the physics teacher. There are four solutions

1. Using Ohm's law to calculate the resistance, the voltage of series resistance U2 = 3.5V, and the bulb current I = U1 / R1, we can know the current I of the resistance. We can use R2 = U2 / I to calculate the resistance. 2. Using the voltage of series circuit is proportional to the resistance, U2 / r2 = U1 / R1, we can directly solve the problem. 3