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A laser emits a narrow beam of light. The radius of the beam is 6.0 mm, and the power is 2.0 mW. What is the intensity of the laser beam?

User Derflo
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Final answer:

To find the intensity of the laser beam, use the formula I = P/A, where P is the power in watts and A is the area in square meters, calculated with A = πr^2 using the radius in meters. The radius should be converted from mm to m, and the power from mW to W before calculating.

Step-by-step explanation:

To calculate the intensity of the laser beam, we can use the formula for intensity I which is defined as the power P per unit area A. Intensity is given by I = P/A. Since we are given the radius r of the beam, we can find the area of the circular beam using the area formula for a circle, A = πr^2. In this case, with a radius r = 6.0 mm, we must first convert this to meters to calculate the area in square meters (m²).

First, convert r to meters: r = 6.0 mm = 0.006 m. Then find the area of the beam: A = π(r²) = π((0.006 m)²) ≈ 1.131×10⁻´ m². Now, we can plug in the values into the intensity formula: I = P/A = 2.0 mW / 1.131×10⁻´ m².

Do not forget to convert the power from milliwatts to watts: 2.0 mW = 2.0×10⁻³ W. The final calculation will give you the intensity of the laser beam in watts per square meter (W/m²).

User Tomasi
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