In a circuit with one cell and one bulb at 0.2A, what will the current be if two more cells and one more bulb are added?

When you have a circuit with one cell and one bulb, the current measured at 0.2A indicates how much charge is flowing through the circuit. In a simple series circuit, the current stays constant through all components.

When two more cells are added, it effectively increases the total voltage supplied to the circuit. Assuming the resistance of the circuit remains constant, Ohm's Law (I = V/R) tells us that if the voltage increases, the current will also increase proportionally.

In this case, adding two more cells (essentially tripling the voltage, if each cell provides the same voltage) will lead to a higher current flowing through the circuit. If we consider that you now have enough voltage to potentially drive the current higher, the most reasonable understanding is that if the circuit allows for increased current flow, the new total could be 0.4A given the initial current was 0.2A. However, since only one more bulb is added but no additional resistance is stated, it is reasonable to state that the increment from 0.2A to 0.3A is more fitting for a simple linear increase due to the gradual addition of voltage.

Therefore, increasing from an original current of 0.