Monochromatic light of frequency `5.0xx10^(14)Hz` is produced by a laser. The power emitted is `3.0xx10^(-3)W`. Estimate the number of photons emitted per second on an avearge by the source. Given `h=6.62xx10^(-34)Js`

Explanation

To estimate the number of photons emitted per second by the laser source, we can follow these steps:

### Step 1: Understand the relationship between power, energy, and number of photons
The power emitted by the laser can be expressed in terms of the number of photons emitted per second and the energy of each photon. The formula is given by:

\[ P = N \cdot E \]

where:
- \( P \) is the power (in watts),
- \( N \) is the number of photons emitted per second,
- \( E \) is the energy of one photon (in joules).

### Step 2: Calculate the energy of one photon
The energy of one photon can be calculated using the formula:

\[ E = h \cdot \nu \]

where:
- \( h \) is Planck's constant (\( 6.62 \times 10^{-34} \, \text{Js} \)),
- \( \nu \) is the frequency of the light (\( 5.0 \times 10^{14} \, \text{Hz} \)).

Substituting the values:

\[ E = (6.62 \times 10^{-34} \, \text{Js}) \cdot (5.0 \times 10^{14} \, \text{Hz}) \]

Calculating this gives:

\[ E = 3.31 \times 10^{-19} \, \text{J} \]

### Step 3: Rearranging the power equation to find the number of photons
Now we can rearrange the power equation to solve for \( N \):

\[ N = \frac{P}{E} \]

### Step 4: Substitute the values into the equation
We know the power \( P = 3.0 \times 10^{-3} \, \text{W} \) and the energy of one photon \( E = 3.31 \times 10^{-19} \, \text{J} \). Substituting these values into the equation gives:

\[ N = \frac{3.0 \times 10^{-3} \, \text{W}}{3.31 \times 10^{-19} \, \text{J}} \]

### Step 5: Calculate the number of photons emitted per second
Performing the calculation:

\[ N \approx \frac{3.0 \times 10^{-3}}{3.31 \times 10^{-19}} \approx 9.05 \times 10^{15} \, \text{photons/s} \]

### Conclusion
The average number of photons emitted per second by the laser is approximately:

\[ N \approx 9.1 \times 10^{15} \, \text{photons/s} \]

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