Video Transcript
Each of the following diagrams
shows a ray entering a thin convex lens. The point marked P is the focal
point of the lens. Before the ray enters the lens, it
is parallel to the optical axis and it passes through the center of the lens. Which diagram correctly shows the
path of the ray after it has passed through the lens? (A), (B), or (C).
In this question, we are asked to
identify the path of a ray of light that passes through a convex lens along the
optical axis. We are told that the ray passes
through the center of the lens. An important rule to remember is
that rays passing through the center of a convex lens will not change direction no
matter what direction the ray approaches from.
Knowing this, let’s look at the
diagrams and see which one shows the correct path of the ray after it passes through
the lens. In options (B) and (C), we see the
rays changing direction when they pass through the lens. So these options are incorrect. This leaves us with option (A). In option (A), the ray does not
change direction after passing through the lens. So option (A) is the correct
answer.
