Multi Lens/Mirror problems and virtual real images

[AriAstronomer]

Hey everyone,
So I'm wondering whether or not a virtual object can make a real image, essentially. Let's say a real object is passed through a diverging lens, and thus creates a virtual image. This image is then bounced off a concave mirror. Now the concave mirror, if given a real object should make a real image (as long as the object is not inside it's focal length). But if given a virtual object, will the image still be virtual, even if it's beyond the focal length??

Thanks,

Ari

 

[netheril96]

Yes, a virtual image can have real images.

 

[Mike Pemulis]

Think about what is happening physically. A virtual image is not a real entity. It's just a label we give to the apparent point of origin of diverging light rays. So in your example, diverging light rays reflect off a mirror and then converge to a point. A real image by definition is a point where actual rays of light meet, which is certainly happening here. So the final image is real.

It is pretty easy to convince yourself that the real-ness or virtual-ness of a final image is completely determined by the last optical element. The intermediate images in between are just mathematical devices that let you use the geometrical optics equations over and over -- but all that's physically happening in the guts of an optical setup is that light rays are either converging or diverging as they travel forward.

 

[AriAstronomer]

Thanks, it's crystal now.