Question

32. Assume the helium-neon lasers commonly used in student physics laboratories have power outputs of 0.500 mW. (a) If such a laser beam is projected onto a circular spot 1.00 mm in diameter, what is its intensity

Answer 1

636.6 W/m²

Step-by-step explanation:

From the given information:

The area of the circular spot can be calculated as:

A = πr²

A = π(0.5 × 10⁻³ m)²

A = 7.85 × 10⁻⁷ m²

The intensity can be determined by using the formula:

`I = (P)/(A)`

`I = \Big ( (0.500 \ mW)/(\pi (0.5 * 10^(-3) \ m )^2) \Big) \Big( (10^(-3) \ W)/(1\ mW) \Big)`

`I = (0.500 * 10^(-3) )/(\pi(0.25 * 10^(-6) ))`

I = 636.6 W/m²