# Snell's Law and critical angle

• xswtxoj
Use the relation to find the critical angle in water.In summary, the critical angle of a plastic in air is 37.3 degrees. To find the critical angle in water, the refractive index of the plastic must be determined and used in the equation n1sin(theta)= n2sin(theta). The critical angle in water is approximately 27.1 degrees.

## Homework Statement

The critical angle of a certain plastic in air is 37.3 degrees. Wats the critical angle of the same plastic if its immersed in water?

## Homework Equations

n1sin( theta)= n2sin(theta)

## The Attempt at a Solution

Nair= 1.00
1.00sin37.3/1.33 = sin(theta)
sin(theta)= .455
inverse sin (theta) = 27.1 degrees

Is that right?

No. I think it should be:
<< complete solution deleted by berkeman >>

Last edited by a moderator:
fiddler crab said:
No. I think it should be:
<< complete solution deleted by berkeman >>

Please do not post complete solutions to homework/coursework questions. Instead, provide hints and tutorial advice. The original poster (OP) must do the buld of the work. The Rules link at the top of the page explains how we treat homework here on the PF.

xswtxoj said:

## Homework Statement

The critical angle of a certain plastic in air is 37.3 degrees. Wats the critical angle of the same plastic if its immersed in water?

## Homework Equations

n1sin( theta)= n2sin(theta)

## The Attempt at a Solution

Nair= 1.00
1.00sin37.3/1.33 = sin(theta)
sin(theta)= .455
inverse sin (theta) = 27.1 degrees

Is that right?
No.
What is the relation between the refractive index and the critical angle?
Find the refractive index of the plastic.

## 1. What is Snell's Law?

Snell's Law is a fundamental principle in optics that describes the relationship between the angle of incidence and angle of refraction when light passes through different mediums.

## 2. What is the equation for Snell's Law?

The equation for Snell's Law is n1sinθ1 = n2sinθ2, where n1 and n2 are the refractive indices of the two mediums and θ1 and θ2 are the angles of incidence and refraction, respectively.

## 3. What is the critical angle?

The critical angle is the angle of incidence at which light passing through a medium is refracted at an angle of 90 degrees, resulting in total internal reflection.

## 4. What factors affect the critical angle?

The critical angle is affected by the refractive indices of the two mediums and the angle of incidence. It is also dependent on the wavelength of light and the surface characteristics of the mediums.

## 5. How is Snell's Law and critical angle used in everyday life?

Snell's Law and critical angle are used in various applications such as optics, telecommunications, and medical imaging. They are also used in the design of lenses, optical fibers, and prisms. In everyday life, we encounter these principles in cameras, eyeglasses, and binoculars.

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