Figure 33–49 is a photograph of an eyeball with the image of a...

Question

Figure 33–49 is a photograph of an eyeball with the image of a boy in a doorway. (a) Is the eye here acting as a lens or as a mirror? (b) Is the eye being viewed right side up or is the camera taking this photo upside down? (c) Explain, based on all possible images made by a convex mirror or lens.

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Accepted Answer

Hello, fellow physicists. Today we want to solve the following practice problem together. So first off, let us read the problem and highlight all the key pieces of information that we need to use in order to solve this problem. In a jewelry store, a large shiny, convex gemstone is placed on display. When a lit candle is positioned nearby, A clearer image of the flame can be seen on the gemstone's curved surface. A photographer captures this image, and the flame appears upright and smaller in the photo. I, does the gemstone act as a lens or a mirror in this scenario? I, I. Is the gemstone surface being viewed right side up, or is the photo taken upside down? III, based on the optical properties of a convex surface, explain why the flame appears upright and reduced in size. Awesome. So it appears for this particular problem we're asked to solve for three separate answers. For part I our first answer, we're trying to figure out if the gemstone will act as a lens or a mirror in this particular situation. For I I our second answer, we're trying to figure out if the gemstone surface is being viewed right side up or if the photos taken upside down. And our last answer we're trying to solve for for part III is based on the optical properties of a convex surface, we're asked to explain why the flame will appear to be upright and reduced in size on this particular gemstone. Awesome. So with that in mind, let's read off our multiple choice answers to see what our final answer might be. So A is the gemstone acts as a lens, the surface is being viewed upside down, and the flame appears upright and reduced because lenses refract light. B is the gemstone acts as a lens. The surface is being viewed right side up, and the flame appears upright and reduced due to the focal properties of a convex lens. C is the gemstone acts as a mirror. The surface is being viewed upside down, and the flame appears upright and reduced due to the reflective nature of a convex smear. And finally, D is the gemstone acts as a mirror, the surface is being viewed right side up, and the flame appears upright and reduced because convex mirrors always create virtual upright and smaller images. Awesome. OK. So first off, in order to solve this problem, let's break it down into our three separate answers that we're trying to solve for. And let's summarize each condition. So this is very important. You need to be able to recall and understand and have a strong understanding of the conceptual physics behind each particular segment or each answer that we're trying to solve, or we need to have the conceptual physics on lock. OK, so for part I, does the gemstone act as a lens or a mirror in this particular scenario? So our answer, so the gemstone will act as a mirror. And the reason why it will act as a mirror, which rather we need to be specific, so specifically, not only does this mirror act, so don't, not only does this gemstone act as a mirror, specifically it's a convex smear. And how do we know it's a convex mirror? So, this conclusion is based on the fact that light from the flame will interact with the outer curved surface of the gemstone and will form an image. If the gemstone were a lens, on the other hand, the light would pass through it and refract, which isn't described in the prom. So right now our gemstone is is not refracting light, rather, it is creating this image on the surface of the gemstone. That is very important to note. So once again, so the gemstone isn't a lens because if it was a lens, the light would pass through it and refract, and this isn't the conditions that are described in the prom itself. Awesome. So for part II, is the gemstone surface being viewed right side up, or is the photo taken upside down? So, we need to note and recall that the gemstone surface is being viewed right side up, and the reason why it's right side up, so is a right. Side up. Awesome. And this is confirmed to be true because convex smears always produce upright images. And and it's irrespective of how the object or the observer is oriented. So this is due to the fact of how the object or the observer is oriented. So it's very important to note that because convex smears always produce upright images, and it is introspective of how the object or the observer is oriented. So the gemstone surface is being viewed upright due to these conditions. Awesome. And then for part III, based on the optical properties of a convex surface, explain why the flame appears upright and reduced in size. So, a convex smear forms a virtual, so this is important to note the keyword is virtual. And it also produces an upright, that is our second keyword, upright and reduced images due to its shape. So virtual upright. Reduced and why is it reduced? And this is all due to. The size, so sorry, due to the shape, not the size, so it's all due to shape. Awesome. So once again, let's quickly recap here. So, a convex mirror forms a virtual upright and reduced images due to its shape. And it's important to note we can break this into 3 separate categories. So, light rays from the candle will strike the convex surface and diverge after reflection. The diverging rays, when extended backwards, will appear to originate from a point behind the mirror, which will create a virtual image. And finally, the convex shape of this gemstone will cause the reflected rays to spread out, leading to a smaller reduced image overall, and this will therefore explain why the flame appears upright and smaller. It's smaller overall, and that's it. We've solved for this problem. Hooray. So looking at our multiple choice answers, the correct answer has to be multiple choice answer letter D. Which states it which states once again the gemstone acts as a mirror, the surface is being viewed right side up, and the flame appears upright and reduced because convex mirrors, convex mirrors always create virtual upright and smaller images. Awesome and that's it. Thank you so much for watching. Hopefully that helped and I can't wait to see you in the next video. Bye.

Key Concepts

Convex Lens and Mirror

Inversion of Images

Image Formation

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