How many electrone flow per second through as electric bulb rated 220V,100W?

Answer

To find out how many electrons flow per second through an electric bulb rated at 220V and 100W, we can follow these steps:

### Step 1: Calculate the Current (I)
The power (P) of an electrical device is given by the formula:
\[ P = V \times I \]
Where:
- \( P \) = Power in watts (W)
- \( V \) = Voltage in volts (V)
- \( I \) = Current in amperes (A)

We can rearrange this formula to find the current:
\[ I = \frac{P}{V} \]

Given:
- \( P = 100W \)
- \( V = 220V \)

Substituting the values:
\[ I = \frac{100}{220} = \frac{5}{11} \, \text{A} \]

### Step 2: Relate Current to Charge Flow
Current (I) is defined as the rate of flow of charge (Q) over time (T):
\[ I = \frac{Q}{T} \]

Since we are looking for the number of electrons flowing per second, we can express charge (Q) in terms of the number of electrons (n) and the charge of a single electron (e):
\[ Q = n \times e \]

Where:
- \( e \) (the charge of a single electron) is approximately \( 1.6 \times 10^{-19} \, \text{C} \).

### Step 3: Substitute and Solve for n
Now, we can substitute \( Q \) in the current equation:
\[ I = \frac{n \times e}{T} \]

For one second, \( T = 1 \), so:
\[ I = n \times e \]

Rearranging for n gives:
\[ n = \frac{I}{e} \]

Substituting the current we found:
\[ n = \frac{\frac{5}{11}}{1.6 \times 10^{-19}} \]

### Step 4: Calculate the Number of Electrons
Now we can calculate \( n \):
\[ n = \frac{5}{11 \times 1.6 \times 10^{-19}} \]

Calculating the denominator:
\[ 11 \times 1.6 \approx 17.6 \]

Thus:
\[ n \approx \frac{5}{17.6 \times 10^{-19}} \]

Calculating the final value:
\[ n \approx 0.284 \times 10^{19} \]

This can be rewritten as:
\[ n \approx 2.84 \times 10^{18} \]

### Final Answer
The number of electrons flowing per second through the electric bulb is approximately:
\[ n \approx 2.84 \times 10^{18} \]

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