Video Transcript
The following figure shows an
object and its virtual image that is formed by light rays reflected from a convex
mirror. Which of the following is not
connected by the straight line that connects all the other choices? (A) The top of the object, (B) the
top of the image, (C) the focal point of the mirror, (D) the center of curvature of
the mirror.
This question is asking us to
identify which of the following is not connected by the straight line that connects
all the other features. Let’s begin by identifying all the
features.
We’ve got the center of curvature,
focal point, and the object itself all labeled in the diagram. Not labeled for us is the image
produced by the convex mirror, which is here. Now that all of the features are
labeled, we can consider the straight lines that connect them. We’re looking for a straight line
that connects three out of four of the answer options.
First, let’s consider the line that
passes through the center of curvature of the mirror and the focal point of the
mirror. This line is aligned with the pink
reflected ray. We can see that although this line
does touch the object and the image, it touches the bottom of these, not the
top. This means it connects only two out
of four of our answer options and isn’t the line that we should consider.
Next, let’s consider the line that
passes through the focal point and the top of the image. We see that this line is along the
blue reflected ray. This line doesn’t pass through
either the center of curvature or the top of the object. So we shouldn’t consider this line
either.
Next, let’s consider the line that
passes through the focal point and the top of the object. This line is aligned with the red
reflected ray. This line doesn’t pass through
either the center of curvature or the top of the image. So we can rule this line out as
well.
The next line we can consider is
the one that passes through the center of curvature and the top of the image. We can see that this also passes
through the top of the object. This means that this line passes
through three out of four of the answer options: the center of curvature of the
mirror, the top of the image, and the top of the object. The only answer option that isn’t
passed through by the straight line is the focal point of the mirror. The focal point is not connected by
the straight line that connects all the other choices.
