What is the light intensity and how to find it ?

[snishanth512]

what are Light intensity, candela and Ste radian ?

How are they related?

How to find these for IR LED?

Suggest some measuring instrument...(Cheapest way)

 

[barry]

candela is a measure of light intensity. steradian is a measure of 3-dimensional (solid) angle. 1 candela is .0015 Watt/steradian.

There are many, many light measuring instruments out there. You need to determine what your requirements are before we can suggest 'the cheapest way'.

 

[peeyushsigma]

light intensity is power or luminous flux divided by solid angle hence its unit is Watt/steradian. for more..
https://en.wikipedia.org/wiki/Light_intensity

 

[snishanth512]

I didn't understand in Wikipedia.

Please explain with diagrams.