Answer:
V = 6.65 [volt]
Step-by-step explanation:
First, we must calculate the power by means of the following equation, where the voltage is related to the energy produced or consumed in a given time.
![P=E/t\\P = 40/30\\P = 1.33[s]](https://img.qammunity.org/2021/formulas/physics/college/cmjbb887gbjzsd0biyfhrtt9wqdranch0e.png)
Using the power we can calculate the voltage, by means of the following equation that relates the voltage to the current.
![P=V*I](https://img.qammunity.org/2021/formulas/physics/college/iawmofrz22fkfiz9dfecinftlqzvo2fgmt.png)
where:
V = voltage [Volts]
I = current = 200 [mA] = 0.2 [A]
![V = 1.33/0.2\\V = 6.65 [volt]](https://img.qammunity.org/2021/formulas/physics/college/mq7dtqn77wd83tr8ctmlu29x8tvej30wux.png)