`AB` is a part of circuit. Find the potential difference `V_(A) - V_(B)` if
a. current `I = 2 A` and is constant,
b. current `i = 2 A` and is increasing at the rate of `1 A s^(-1)`,
c. current `i = 2 A` and is decreasing at the rate `1 A s^(-1)`,

Explanation

Applying `KVL` from `A` to `B`,

`V_(A) - 1(di)/(dt) - 5 - 2i = V_(B)`
a. Put `i = 2, (di)/(dt) = 0, V_(A) - 5 - 4 = V_(B)`
`:. V_(A) - V_(B) = 9V`
b. Put `i = 2, (di)/(dt) = 1`
`V_(A) - 5 - 4 = V_(B)`
or `V_(A) - V_(B) = 10 V`
Put `i = 2, (di)/(dt) = -1`
`V_(A) + 1 - 5 - 2 xx 2 = V_(B)`
`V_(A) = 8V`