Get a sheet of paper and draw a horizontal optical axis. Next,
draw a vertical line near the center of the optical axis to
represent your lens, then measure out and draw the focal points.
Assume the focal length to be 2cm. Pick an object point 6cm away
from the lens on the top left-hand side of the paper. Draw the
three simple case rays – parallel, through the center of the lens,
and through the focal point – and...