How far should the slide be from the overhead projector lens? How does the slide image appear on the screen?

The slide from the overhead projector lens is at a distance greater than the focal length of the lens, and the image will turn upside down and enlarged.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.