Question

mention the rules for obtaining iamges by convex lens​

Answer 1

Rule 1: A ray of light which is originally parallel to the principal axis passes through the focus after refraction through the lens.

Rule 2: A ray of light passing through the optical centre of the convex lens does not bent after refraction but goes straight. Also, a ray of light going along the path of principal axis of a convex lens also goes straight and does not deviate.

Rule 3: When a ray of light passes through the focus of the convex lens then it becomes parallel to the principal axis after refraction through the lens.