What's is the question asking, true or false?
Answer:

Explanation:
As we know that the energy stored in the capacitor is given as

here we know that

also we know that

now we have


now we know the formula of capacitance



Answer:
10 V
Explanation:
The potential difference between two points is the amount of work required to carry a unit charge from one point to the other point. This would result in a potential difference between this two points.
The difference between the potential across two points B and A is 
From the image attached:

The gravity is pushing rhe boat down