A lightbulb is connected to a battery to form a circuit. At first, the lightbulb shines normally. However, a small demon now sits beside the circuit, at a point just before the charge carriers enter the battery. Every so often, the demon adds some new charge carriers to the circuit at this point. Therefore, Kirchhoff's first law is NOT conserved anymore. What will happen to the lightbulb? Assume that the rate at which a charge carrier moves round the circuit does not change.
1) The brightness of the lightbulb will not change. Charge carrier number is not conserved, but the total energy given to all the charge carriers is, so the supply of energy to the bulb is the same.
2) The battery will find it harder to push the greater number of charge carriers round the circuit, so more energy will go into that. The lightbulb will therefore get dimmer.
3) The potential energy the demon gives to each charge is not specified, so it is not possible to know.
4) Each charge carrier still gets the same amount of energy from the battery, so the total energy supplied to the bulb goes up, and the bulb will get brighter.