For a real battery the work done by battery is equal to increase in electrical potential energy of a positive charge as charge moves from negative terminal to positive terminal of battery

Is this above statement true. ??

Q. The flows from positive to negative terminal of the battery where as the flow from negative to positive terminal of the battery

Q. A $10\mu F$ capacitor charged to $20V$ is connected across a $15V$ battery through a switch such that positive terminal of battery is connected to negative charged plate of capacitor. When switch is closed, work done by battery of $15V$ in long time will be

Q. A battery is of emf E is being charged from a charger such that positive terminal of the battery is connected to terminal A of charger and negative terminal of the battery is connected to terminal B of charger. The internal resistance of the battery is r.

Q. A $10\mu F$ capacitor charged to $20V$ is connected across a $15V$ battery through a switch such that positive terminal of battery is connected to negative charged plate of capacitor. When switch is closed, work done by battery of $15V$ in long time will be

Q. A parallel plate capacitor of capacitance $C$ is connected to a battery and is charge to a potential difference $V$. Another capacitor of capacitor $2C$ is similarly charged to a potential difference $2V$. The charging battery is now disconnected and the capacitors are connected in parallel to each other in such a way that the positive terminal of one is connected to the negative terminal of the other. The final energy of the configuration is: