$\overline{)\begin{array}{rcl}{\mathbf{Power}}{\mathbf{,}}{\mathbf{}}{\mathbf{P}}& {\mathbf{=}}& \frac{\mathbf{E}\mathbf{n}\mathbf{e}\mathbf{r}\mathbf{g}\mathbf{y}\mathbf{,}\mathbf{}\mathbf{E}}{\mathbf{t}\mathbf{i}\mathbf{m}\mathbf{e}\mathbf{,}\mathbf{}\mathbf{t}}\end{array}}$

$\overline{)\begin{array}{rcl}\mathbf{1}\mathbf{Watt}\mathbf{,}\mathbf{}\mathbf{\left(}\mathbf{W}\mathbf{\right)}& {\mathbf{=}}& \frac{\mathbf{1}\mathbf{}\mathbf{Joule}\mathbf{}\mathbf{\left(}\mathbf{J}\mathbf{\right)}}{\mathbf{1}\mathbf{}\mathbf{second}\mathbf{}\mathbf{\left(}\mathbf{s}\mathbf{\right)}}\end{array}}$

$\overline{)\begin{array}{rcl}\mathbf{Intensity}\mathbf{,}\mathbf{}\mathbf{I}& {\mathbf{=}}& \frac{\mathbf{P}\mathbf{}\mathbf{\left(}\mathbf{W}\mathbf{\right)}}{\mathbf{Area}\mathbf{}\mathbf{\left(}{\mathbf{m}}^{\mathbf{2}}\mathbf{\right)}}\end{array}}$

Laser beams are sometimes used to burn away cancerous tissue.

What is the intensity, in watts per square meter, of a laser beam that is 90.0% absorbed by a 1.95-mm diameter spot of cancerous tissue and must deposit 495 J of energy to it in a time period of 4.15 s?

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Energy Carried by Electromagnetic Waves concept. You can view video lessons to learn Energy Carried by Electromagnetic Waves. Or if you need more Energy Carried by Electromagnetic Waves practice, you can also practice Energy Carried by Electromagnetic Waves practice problems.