Question Video: Understanding the Center of Curvature of a Concave Mirror Science • Third Year of Preparatory School

Video Transcript

For any spherical mirror, the distance between the center of curvature and the center of the surface is just the radius of that sphere. Which one of the following sentences correctly describes the location of the center of curvature of a concave mirror? (A) The center of curvature of a concave mirror will always be on the side opposite to the observer. (B) The center of curvature of a concave mirror will always be on the same side as the observer. (C) Depending on the path of the light rays, the center of curvature of a concave mirror can sometimes be on the side opposite to the observer and can sometimes be on the same side as the observer.

To start figuring out which of these three answer options is correct, let’s sketch a curved mirror. And we’ll say that this is a concave mirror. A concave mirror is one where light always enters into the curved portion of the mirror, here on this side. This is the opposite of light being incident on the mirror from this side. All of our possible answers talk about which side of a concave mirror an observer will be on. In order to observe or see the way a concave mirror reflects light, an observer always needs to be on the same side of the mirror as the incoming rays of light. An observer of a concave mirror then is always facing this curve of the mirror shape.

We can recall that this shape is part of a larger circle. The center of that circle, located here, is called the center of curvature of the mirror. For a concave mirror then, the center of curvature of the mirror and an observer are always on the same side of the mirror. What we’re finding is that answer option (B) is the correct description of a concave mirror. The center of curvature of a concave mirror will always be on the same side as the observer.