Warm-Up Exercise 28

Due 12:15 pm, Wed 31 Oct 2012

Physics 123, Fall 2012

Reading assignment: 36.1-36.2

While decorating your Christmas tree you notice that you can see yourself in one of the spherical, reflective ornaments. Is your image real or virtual? How do you know?

It's virtual. You can tell because the image appears to be "inside" the ornament. That's a dead giveaway for virtual images. By contrast, a real image is one where the light from the image is REALLY coming from a certain point in space, not just appearing to do so. That's generally only possible if the image is "floating" in the air.

Will a converging (concave) mirror ever produce a focused image at the focal point? If yes, when? If not, why not?

No, or at least not unless the object is infinitely far away. Otherwise you can tell from the "mirror equation" that q (the place where the image is focused) will never be equal to f (the focal point).

What does it mean for a mirror to have a large "radius of curvature"?

That means the mirror does NOT curve very much. That is, it's close to flat.

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