Video Transcript
The following figure shows writing
on an ambulance that is viewed by reflection from a mirror. Which of the following correctly
shows how the writing would appear if viewed directly from a position in front of
the ambulance? Is it (A), (B), (C), or (D)?
In this question, we want to know
how the writing of the word “AMBULANCE” would appear if we were standing right in
front of the actual ambulance. Looking at our answer choices, it
might seem that option (B) must be correct, since this shows the word as we would
normally see it printed. In fact, option (B) is not the
correct answer.
To understand this, let’s clear
some space and consider this sketch. Here, we see the person viewing the
word after it is reflected in the mirror and also the person standing directly in
front of the ambulance seeing the word. Light rays from the object reflect
off the mirror and reach the first person. This is how that person sees the
word.
We see from our diagram that in the
mirror, the word “AMBULANCE” looks like this. Now let’s think about light rays
coming from the printed word and reaching a viewer directly. From this person’s perspective, the
top of the word is here, the bottom is here, the right is here, and left is
here. If we write the word oriented this
way, it would look like this. This is how the person looking
directly at the ambulance reads it. We could say that the letters are
right-side up but reversed from left to right.
The word appears this way in answer
option (A). Therefore, this is our final answer
for how the writing on the ambulance would appear if viewed from directly in front
of the ambulance.
