light.intensity shows error

i am using Unity 5.4.1

whenever i write "light. " its is not showing ‘intensity’ option

and light.color too

it shows an error on “color” and “intensity”

GameObject.light is obsolete.
Create a private Light and set it with GetComponent<Light>()
After that you can adjust the private Light reference.
Or use getcomponent everytime without caching it.

what’s the difference b/w Light ,light
@Ju_M
is there any PDF available for Beginners