Answer
(a) 2
(b) Infinitely many rays from this point actually strike the lens and refract to the image point.
Work Step by Step
(a) We can trace rays from a point on an object to see where the rays intersect, and this point of intersection is the image point. As soon as two rays intersect, we know where the image point is formed.
Therefore, the minimum number of rays needed to locate an image point is $~~2$
(b) Any ray from the point on an object that travels through the lens will intersect the image point. Since rays can be traced in infinitely many directions, infinitely many rays from this point actually strike the lens and refract to the image point.
