Question

Define first principal axis and second principal axis ?

Answer 1

Principal axis may refer to:

One of the two principal axes of a hyperbolaPrincipal axis (mechanics)Aircraft principal axesPrincipal axis theoremPrincipal axis (crystallography)Optical axis

Answer 2

Answer:

• The distance of the first principal axis from the centre of the lens is known as the first principle focal length.
• The second principal focus of a lens is the position of the image on the principal axis of the lens, when the object is formed at infinity.