How the image on film or on the screen will change when showing

How the image on film or on the screen will change when showing transparencies using a projection lamp, if you close half of the lens. explain the answer.

It is likely that nothing can change on film.
Let’s see what will be done on the screen.
There is a photographic lens between the film and the screen, and a beam of illumination passes between each point on the film and each point corresponding to it on the screen. If we cover half of the lens, fifty percent of this beam of illumination will be cut off, but this will not affect the rest of the beam at all.
This means that the point on the screen will be in the same place, but the lighting will be less suitable for it.
Conclusion – the picture will not move, but it will be less colorful.