1. This makes spearfishing very difficult!
Apparent Depth
When viewed from another medium, objects appear to have a different depth than they actually do.
This makes spearfishing very difficult!

2. The photographs show a bathroom basin. In Figure 1 the basin is empty.
In Figure 2 the basin is full of water.
Both photographs were taken from the same position.
Photograph 1 Photograph 2
In photo 2 the plug is visible and the basin appears shallow compared to photo 1

3. empty basin full basin normals camera camera
Explain in detail (and with the help of diagrams) why an image of the plug can only be seen by the camera when the sink is filled up with clear water.

4. E Excellence empty basin camera full basin normals camera
Light ray to camera is blocked when sink is empty
full basin
normals
camera E
Refraction of light at an interface
Water and air are the two mediums
The empty basin’s edge blocks the view of the plug.
When the basin is full of water the light rays from the plug bend away from the normal at the water/air interface.
The rays bend towards the camera (away from the normal) so the plug can be viewed.

5. normal nair = 1.05 The photo shows the plug in a bathroom basin.
The basin is full of water.
The diagram shows how the light is refracted.
The angle of incidence is 370
The angle of refraction is 500
Calculate the refractive index of the water.
normal
nair = 1.05

6. M Merit The angle of incidence is 370 The angle of refraction is 500
Calculate the refractive index of the water.
nair = 1.05
normal
50o
37o M
Merit

7. Our eyes perceive the blue sky and can mistake it for water.
Mirages
The warm air has a lower density (larger n –moves slower) and so light totally internal reflects before hitting the ground.
Our eyes perceive the blue sky and can mistake it for water.

8. Light from a ship can totally internal reflect and reach an observer creating an inverted image
Warm air (small n)