~My dog and a flat mirror:
~In this picture, my dog is lying on my bed facing me and behind her is a flat mirror (door of my closet). In the mirror, you can see my dog's backside which is the side that is facing the mirror. But is that a real image? Is she really behind that mirror? Or is it just a virtual image that our mind puts together?
~ Light rays from her head that go straight towards the mirror will reflect back as it is perpendicular to the mirror. That ray itself would be where the normal line would go. Another ray that I drew from her head hit the straight mirror at an angle. I had to draw a normal line to determine the angle of incidence. I calculated a 25° angle. This means that the angle of reflection is 25°. Looking at the two rays of reflection from the head of my dog, they will never intersect at any point. This makes it a virtual image because it does not connect at any point in front of the mirror.
~ So I traced back the angles of reflection all the way behind the mirror. And of course, they intersected at a point virtually. This virtual image connected at the same height as the object and the same distance away from the mirror. This is why my dog's reflection looks like she is the same distance away from the mirror.
~ To determine the size of the reflected, virtual image, I drew a ray from one of her paws straight towards the straight mirror. It also reflects back at the same line because it is perpendicular to the mirror. I drew another incidence ray at an angle and drew a normal line to determine the angle of incidence. It was also 25° which means the angle of reflection would be 25°. These two rays of reflection also would never intersect at a real point. So our mind tricks us into seeing a virtual image where the intersect at a point behind the mirror. After drawing the reflected image, I determined that it was VIRTUAL, the SAME SIZE, the SAME DISTANCE, and UPRIGHT.
