Is it possible for one ray to be shorter in length than another?

Yes, even light rays can vary in wavelength and frequency, if the length of the ray is sorter, it becomes more energetic and has a higher frequency. If you're talking about a ray tracing diagram for lenses or mirrors, the length of the ray doesn't really matter unless you're finding the path length but there are some procedures for that too. Let me know if I missed what you were asking.

When the apple falls from the tree, it has some gravitational potential energy due to its height. Now, When it starts falling, the Gravitation Potential energy will starts converting into the Kinetic Energy. When the apple is about to strikes the ground, the Gravitational Potential energy have been converted into the Kinetic Energy.

Explanation: