By definition:
"The secondary focal point is where rays that are parallel when they enter the lens cross or appear to have crossed."
Focal length is measured in milimeters (mm) -----------------------------------------------------------------
Focus (only at the focal point if the incoming rays are all parallel to the axis).
Focal length is related to the lens. It has nothing to do with how near or far the object is to the lens or objective.
It should be parallel. Rays "parallel to the principle axis of a concave mirror converage at or near the focal point.
the focal length
In art a composition's focal point is actually called the focal point. There may be multiple focal points, in which case the main one is the focal point and the others are secondary focal points. You can recognize the focal point because it is somehow set apart from the rest of the composition.
2 inches.
four years
It is an equilateral triangle
It depends on what breed of cat.
The Leangth of a flower stem us 5 in.
Scissors come in many different lengths.
No. But they can be the lengths (not leangths!) of the three sides.
Panda's claws AREN'T a certain leangth. The size varies.
four times the initial value
the prefix for focal is infocals
focal length of the lens