What is the critical angle and area for light at a water and air interface?

In summary, the critical angle for light at a water-air interface with n=1.33 and n=1 is 48.75 deg. To calculate the area at the surface for a fish 2m below the water, basic trigonometry can be used to find the sides and angles of the triangle. The resulting area is 2.28 m^2, representing the circular disk of bright blue sky directly above the fish up to 48 degrees.
  • #1
mogley76
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Homework Statement


calculate the critical angle for light at a water (n=1.33) and air (n=1) interface.
if a fish is 2m below the surface of the water , calculate the area at the surface through which the fish can viw the world above the water.

Homework Equations



none given

The Attempt at a Solution



critical angle = sin theta c= n2/n1 = 48.75 deg

area of surface=

using basic trig find out all the sides and angles of triangle ..
then area of tribgle is .5*2.28*2 = 2.28 m^2

am i right in all this??
 
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  • #2
the Area on the SURFACE that the fish sees thru ...
it looks like a circular disk of bright blue sky directly above the fish ... out to 48deg.
 

1. What is the critical angle?

The critical angle is the angle of incidence at which light is refracted at an angle of 90 degrees. This means that light travels along the surface of a medium, rather than entering or passing through it.

2. How is the critical angle calculated?

The critical angle can be calculated using Snell's Law, which states that the ratio of the sine of the angle of incidence to the sine of the angle of refraction is equal to the ratio of the indices of refraction of the two materials.

3. What is the relationship between critical angle and total internal reflection?

The critical angle is the minimum angle at which total internal reflection can occur. If the angle of incidence is greater than the critical angle, the light will be reflected back into the medium rather than being refracted out.

4. How does the critical angle change with different materials?

The critical angle is dependent on the refractive indices of the two materials involved. Materials with a higher refractive index will have a smaller critical angle, meaning that total internal reflection can occur at smaller angles of incidence.

5. What is the significance of the critical angle in optical fibers?

The critical angle plays a crucial role in the function of optical fibers, as it allows for the transmission of light signals through the fiber via total internal reflection. This allows for efficient and high-speed communication over long distances.

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