CBSE · Class 10 · Science · Light – Reflection and RefractionWhat is the principal focus of a convex lens?

The principal focus of a convex lens is a specific point on its principal axis where parallel rays of light, traveling parallel to the principal axis, actually converge after passing through and refracting from the convex lens. Since the light rays genuinely meet at this location on the other side of the lens, a convex lens possesses a real principal focus. The distance measured from the optical center of the convex lens to this principal focus is defined as its focal length, which is positive.