Finding the intensity of radiation ?

[mkbh_10]

I have a 150 W Xenon lamp with me and I need to know what is the intensity(W/m^2) of light being radiated on a surface at x distance away . How do I do it ?

Can I use a photodiode, if yes then how ?

 

[MisterX]

You could look for a photometer which can output irradiance for visible light.

 

[technician]

I can tell you how to CALCULATE the intensity if you assume that 150W is all light.
The 150W passes through the surface of a sphere of radius r as it spreads out (assuming no absorption by the air) so the theoretical intensity = 150/(4πr^2) W/m^2
I am certain that this is not a good enough answer for you but it will give you a maximum value and if you have more data about the bulb then I hope it is of some use.
good luck