which is unnecessary to include when accurate...
which is unnecessary to include when accurately drawing ray diagrams? focal point lens focal length three easy rays
Answer
# Brief Explanations:
In ray - diagram drawing for lenses, the focal point, the lens itself, and the focal length are fundamental elements. While the three - easy rays (parallel to the axis, through the focal point, and through the optical center) are a convenient method to find the image position, they are not necessary for an accurate ray diagram in the strictest sense. One can use other rays and geometric optics principles to draw the diagram.
# Answer:
three easy rays