A laser emits a narrow beam of light The radius of the beam
     A laser emits a narrow beam of light. The radius of the beam is 8.9 mm, and the power is 2.9 mW. What is the intensity of the laser beam Number  Units 
  
  Solution
Intersity is power transmitted per unit area.
I=P/A.
Power P= 2.9mW
Area= pi*r^2 = 3.14*(8.9*10^-3)^2 = 248.7x10^-6 m^2
Intensity = 11.66W/m^2

