Question

Incident ray X passes parallel to the principal axis of a concave lens. Incident ray Y passes parallel to the principal axis of a convex lens.

How do the rays behave differently after passing through each lens?

Ray X continues moving in the same direction, and ray Y refracts and passes through the focal point located behind the lens.
Both rays refract and move as though they passed through the focal point.
Ray X appears as though it passed through the focal point in front of the lens, and ray Y passes through the focal point on the other side of the lens.
Both rays continue moving in the same direction.

Answer 1

"Ray X appears as though it passed through the focal point in front of the lens, and ray Y passes through the focal point on the other side of the lens."

Explanation: A concave (diverging) lens makes a ray parallel to the axis diverge as if it came from the focal point on the same side as the incoming light (virtual focus). A convex (converging) lens brings a parallel ray to a real focus on the opposite side.