Video Transcript
Which of the mirrors in the diagram
below is a concave mirror? Incident light is shown by the
yellow lines.
Here we see two mirrors, Mirror 1
and Mirror 2. The difference between them is the
way that they’re curved with respect to the incoming light. Mirror 1, we see, is curved
outward, bulging towards the incoming light, we could say. Opposite to this is mirror 2, which
we see is curved inward. We want to know which of these two
mirrors is a concave mirror. One way we can remember the shape
of a concave mirror is to think about the word cave in this name. Just like a cave is something that
we travel into, a concave mirror, we could say, is something that light travels into
inside this curving arc. Because the light reaching Mirror 2
is entering into the curve of the mirror, we know that this mirror is concave.
Of these two mirrors then, Mirror 2
is the concave mirror.
