Calculating the Current:

To calculate the current, we need to use the formula:

I = Q / t

where I is the current, Q is the charge, and t is the time.

Given:
Charge (Q) = 1 billion electrons = 1 x 10^9 electrons
Time (t) = 10^-4 seconds

Substituting the values into the formula:

I = (1 x 10^9) / (10^-4)

Simplifying:

I = 1 x 10^13 A

Hence, the current is 1 x 10^13 Ampere.

Direction of Current:

The direction of current is the direction in which positive charges flow. In conventional current flow, we consider the flow of positive charges from a higher potential to a lower potential. However, in reality, electrons are negatively charged particles and flow in the opposite direction, from lower potential to higher potential.

So, in this scenario, the current is actually the flow of electrons from point B to point A. This is known as electron flow or electronic current. Therefore, the direction of current in this case is from point B to point A.

Explanation:

When one billion electrons pass from point A to point B in a time interval of 10^-4 seconds, we can calculate the current using the formula mentioned above. The current is a measure of the rate of flow of charge, and it is measured in Amperes (A).

In this case, we are given the charge (1 billion electrons) and the time (10^-4 seconds). By substituting these values into the formula, we can calculate the current.

It is important to note that the direction of current is the direction in which positive charges flow. However, since electrons are negatively charged particles, they flow in the opposite direction. Therefore, the direction of current in this case is from point B to point A.

Overall, the current is 1 x 10^13 Ampere, and its direction is from point B to point A due to the flow of electrons.