# Question Video: Recognizing Concave Lenses with Different Radii of Curvature Science

Which of the following is not a concave lens? [A] Figure A [B] Figure B [C] Figure C [D] Figure D [E] Figure E

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### Video Transcript

Which of the following is not a concave lens: (A), (B), (C), (D), or (E)?

First, let’s recall that a concave lens is an object made of transparent material that light can pass through. As the light passes through the lens, it changes direction. When viewed from the side, a concave lens has this shape. This shape can be drawn using two spheres and a cylinder. If we view these shapes from the side and arrange them so they overlap like this, we get the outline of a concave lens. Concave lenses are thinner in the middle of the lens and thicker at the edges, and they have two curved sides.

If we look at options (A), (B), (C), and (D), we see that all of these shapes match this description. These shapes are all thinner in the middle and thicker at the edges and they have two curved sides. These shapes could all be formed using two spheres and a cylinder, like we described before. On the other hand, option (E) is S shaped. It is the same thickness in the middle as it is at the ends, and so it is not the correct shape for a concave lens. So, the correct answer is that option (E) is not a concave lens.