Answer:
[tex]35716560 W/m^2[/tex]
Explanation:
1.95 mm = 0.00195
Suppose the cancerous tissue has a circular shape with area of
[tex]A = \pi d^2/4 = \pi*0.00195^2/4 = 3 \times 10^{-6} m^2[/tex]
The actual energy output of the laser beam with 90% efficiency is
[tex]E = 90% * 480 = 432 J[/tex]
The power of this energy over 4.05 s time period per square meter is
[tex] P = E/(A*t) = 432/( 3 \times 10^{-6} * 4.05) = 35716560 W/m^2[/tex]
