Question

Assume a laser has a power outputs of 0.4 mW. If the laser beam is projected onto a circular spot 1.83 mm in diameter, what is its intensity in W/m² ?

Answer 1

The intensity of the laser beam is approximately 172.36 W/m².

Step-by-step explanation:

To find the intensity of the laser beam, we need to calculate the power per unit area.

First, we need to find the area of the circular spot. The diameter is given as 1.83 mm, so the radius is half of that, which is 0.915 mm.

The area of the circle is given by the formula A = πr², where r is the radius. Plugging in the given value, the area is A = π(0.915 mm)².

Next, we convert the diameter and radius to meters to ensure consistency in units. 1.83 mm is equal to 0.00183 m, and 0.915 mm is equal to 0.000915 m.

Now, we can calculate the area in square meters: A = π(0.000915 m)².

Finally, we can find the intensity by dividing the power output of the laser (0.4 mW) by the area (which we calculated as A = π(0.000915 m)²).

So, the intensity of the laser beam in W/m² is approximately 172.36 W/m².