Answer to Question #210552 in Optics for Tawanda

Question

Describe image formation by a flat refracting surface and state the image location

Answer 1

When rays of light propagate from one medium to another, these rays undergo refraction, which is when light waves are bent at the interface between two media.

The refracting surface can form an image in a similar fashion to a reflecting surface, except that the law of refraction (Snell’s law) is at the heart of the process instead of the law of reflection.

Snell's law

$\mu=\frac{sin i}{sinr}$

Refraction at a Plane Interface—Apparent Depth

If you look at a straight rod partially submerged in water, it appears to bend at the surface .

The reason behind this curious effect is that the image of the rod inside the water forms a little closer to the surface than the actual position of the rod, so it does not line up with the part of the rod that is above the water. The same phenomenon explains why a fish in water appears to be closer to the surface than it actually is.

Bending of a rod at a water-air interface. Point P on the rod appears to be at point Q, which is where the image of point P forms due to refraction at the air-water interface.