Voltage and current across a lamp?
A 3 V flashlight battery has an internal resistance of 1 ohm when new and 10 ohms when old. (Imagine this as a resistor in series with the battery mounted inside the battery itself, which describes the chemical degradation of the battery with age.) What is the voltage across a 10 ohm lamp (the load) and the current through the lamp when the battery is new and when it is old?
Thank you very much!
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The total resistance in the circuit when the battery is new is 11 ohms, so the current is 3/11 = 0.272 amp and the voltage across the lamp is 10(0.272) = 2.72 V/
When the battery is old the total resistance is 20 ohms, so the current is 3/20 = 0.15 amp and the voltage across the lamp is 10(0.15) = 1.5 V.