You have a light ray and a normal.
Find the angle between them to find the light's intensity at the point?
L = plane - lightPoint
cos(N.L) = light intensity at point P?
Sorry this is a bit misleading.
Intensity = Ip * kd * cos(N.L)
Sorry, this is an exam question I just want to know the answer.
I forgot to cos the N.L and got an answer of -8 for the dot-prod of the 2 vectors.
Ip = 150
Kd = 0.6
N.L = -8
I = 150 * .6 * cos(-8)
I = 89.124
All other lightsources don't exist(ambient, specular) and neither does a reflection nor a viewer come into play.
I eat coffee.