Question

define principal focus?​

Answer 1

Explanation:

Focus is the point where light rays originating from a point on the object converge. The principal focus is defined as the point where a beam parallel to the principal axis appears to diverge converges from a point on the principal axis after passing through the lens

Answer 2

Answer:

focus is the point where light rays originated from a point on object converge. the principal focus is defined as the point where a beam parallel to a principal axis appear to diverge converges from a point on the principal axis after passing through the lens.