**Calculating the Current in a Hydrogen Atom**

To calculate the current in a hydrogen atom based on the number of revolutions made by an electron in one second, we need to understand the concepts of current, charge, and the revolution of electrons in an atom.

**1. Current:**
Current is the flow of electric charge per unit time. It is measured in Amperes (A) and is defined as the rate of flow of charge through a conductor.

**2. Charge of Electron:**
The charge of an electron is a fundamental property of an electron. It is represented by the symbol "e" and is approximately equal to -1.6 x 10^-19 Coulombs (C).

**3. Revolution of Electron in a Hydrogen Atom:**
In a hydrogen atom, the electron revolves around the nucleus in specific orbits or energy levels. These orbits are called shells, and each shell has a fixed number of electrons. The electron can jump from one shell to another by absorbing or emitting energy.

**Calculating the Current:**

1. The given information states that the electron in a hydrogen atom makes 6.25 x 10^15 revolutions in one second. This means that the electron completes 6.25 x 10^15 orbits around the nucleus in one second.

2. To calculate the current, we need to determine the charge passing through a given point in one second. Since each revolution of the electron completes one full circle, the charge passing through a given point is equal to the charge of a single electron.

3. We know that the charge of an electron is -1.6 x 10^-19 C. Therefore, the total charge passing through a given point in one second is (-1.6 x 10^-19 C) x (6.25 x 10^15 revolutions).

4. By multiplying these values, we can find the total charge passing through the point in one second.

5. The current is defined as the rate of flow of charge. Therefore, to find the current, we divide the total charge passing through the point in one second by the time taken, which is 1 second.

6. Finally, we can calculate the current by dividing the total charge by the time taken:

Current = Total Charge / Time = (-1.6 x 10^-19 C x 6.25 x 10^15) / 1 = -1.0 A

Therefore, the current in the hydrogen atom is -1.0 Ampere (A).

**Explanation:**

In a hydrogen atom, the electron revolves around the nucleus in specific orbits. The given information states that the electron completes 6.25 x 10^15 revolutions in one second. By considering each revolution as the charge passing through a given point, we can calculate the total charge passing through the point in one second. Dividing this total charge by the time taken (1 second), we find the current in the hydrogen atom to be -1.0 Ampere (A). The negative sign indicates that the direction of the current is opposite to the direction of the flow of electrons.