One billion electrons pass from a point P towards another point Q in `10^(-3)` s. What is the current in ampere ? What is its direction ?

Answer

To solve the problem, we will follow these steps:

### Step 1: Identify the number of electrons and the time interval
We are given that one billion electrons pass from point P to point Q in \(10^{-3}\) seconds.

- Number of electrons, \(n = 10^9\)
- Time, \(t = 10^{-3}\) seconds

### Step 2: Determine the charge of one electron
The charge of one electron is approximately \(e = 1.6 \times 10^{-19}\) coulombs.

### Step 3: Calculate the total charge that passes through
The total charge \(Q\) that passes through can be calculated using the formula:
\[ Q = n \times e \]
Substituting the values:
\[ Q = 10^9 \times 1.6 \times 10^{-19} = 1.6 \times 10^{-10} \text{ coulombs} \]

### Step 4: Calculate the current using the formula
Current \(I\) is defined as the charge per unit time:
\[ I = \frac{Q}{t} \]
Substituting the values we found:
\[ I = \frac{1.6 \times 10^{-10}}{10^{-3}} = 1.6 \times 10^{-7} \text{ amperes} \]

### Step 5: Determine the direction of the current
The direction of conventional current is opposite to the flow of electrons. Since the electrons are moving from point P to point Q, the current direction will be from point Q to point P.

### Final Answer
- The current is \(1.6 \times 10^{-7}\) amperes.
- The direction of the current is from Q to P.

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