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In: Physics

What is the intensity in W/m² of a laser beam used to burn away cancerous tissue...

What is the intensity in W/m² of a laser beam used to burn away cancerous tissue that, when 93.5% absorbed, puts 493 J of energy into a circular spot 2.13 mm in diameter in 3.70 s?

_______________W/m²

How many times more intense is this than the maximum intensity of direct sunlight (about 1360 W/m²)?

_______________

Expert Solution

Energy E = 493 J

Diameter d = 2.13 mm

Radius r = d/ 2

= 1.065 mm

=1.065 x10 ^-3 m

Area of crosssection A = r ²

= 3.56x10 ^-6 m ²

Time t = 3.7 s

Power P = E / t

= 133.24 W

Intensity absorbed I = P /A

= 37.39 x10 ⁶ W / m²

Intensity of laser beam I ' = I / 0.935

= 40 x10 ⁶ W m²

(b). required number = I ' /(1360 W/m ²)

= 29408.9

genius_generous answered 1 hour ago

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