Exploring Critical Angles of Snell's Law

In summary, Snell's Law of Angles states that the ratio of the sines of two angles in a medium is equal to the ratio of the refractive indices of the two media. However, in order to find the critical angle, one of the angles must be 90°. This is because for total internal reflection to occur, the refractive index of the second medium must be smaller than the first. This means that nB/nA < 1. It is not possible for sinA to be greater than 1, which is why there cannot be a critical angle when nB/nA > 1. The confusion may arise when comparing the refractive indices of different media, such as glass and air or water and
  • #1
ZxcvbnM2000
64
1
Snell's Law of Angles says that : sinA/sinB = nB/nA

but in order to find critical angles B has to be 90° . I understand that in order to have total internal reflection that nB/nA < 1 but why can't there be a CRITICAL angle when nB/nA > 1 ?

sinA would have to be greater than 1 which cannot happen but if i do it separately : glass to air and water to air and say that air-n-water = nwater/nair it is 1.33/1.5 which is true but if i do it in one go it is 1.5 / 1.33 . I must be doing something wrong , because this seems too easy :S
 
Physics news on Phys.org
  • #2
What do you mean by "if i do it in one go"?
 

Related to Exploring Critical Angles of Snell's Law

1. What is Snell's Law?

Snell's Law, also known as the law of refraction, is a formula that relates the angles of incidence and refraction of a light ray as it passes through the boundary between two different materials, such as air and water.

2. What are critical angles in Snell's Law?

Critical angles are specific angles of incidence at which a light ray will be refracted at an angle of 90 degrees, resulting in total internal reflection. These angles are dependent on the refractive indices of the materials involved.

3. Why is it important to explore critical angles of Snell's Law?

Exploring critical angles of Snell's Law allows us to understand the relationship between the angles of incidence and refraction, and how this affects the behavior of light as it passes through different materials. This knowledge is crucial in various applications, such as optics, telecommunications, and medical imaging.

4. What factors affect the critical angle in Snell's Law?

The critical angle is primarily affected by the refractive indices of the two materials at the boundary. A higher refractive index results in a smaller critical angle, while a lower refractive index results in a larger critical angle. The wavelength of light and the angle of incidence also play a role in determining the critical angle.

5. How is Snell's Law used in real-world situations?

Snell's Law is used in many real-world situations, such as designing lenses for cameras and eyeglasses, determining the optimal angle for light to enter a fiber optic cable, and understanding the behavior of light in different mediums for medical procedures like laser eye surgery. It is also used in the field of geology to study the properties of minerals and rocks based on their refractive indices.

Similar threads

Solve Snell's Law: Glass Cube Refractive Index = 1.77
    • Introductory Physics Homework Help
Replies
8
Views
4K
Total Internal Reflection and Transmitted Wavelength
    • Introductory Physics Homework Help
Replies
1
Views
157
Geometrical optics: using Snell's law, find the depth of the pool
    • Introductory Physics Homework Help
Replies
6
Views
1K
I How can I derive this relation from Snell's law?
    • Optics
Replies
1
Views
1K
A How to compute phase gradient from Snell's law?
    • Optics
Replies
1
Views
1K
Snell's law problem about a hemispherical glass ball
    • Introductory Physics Homework Help
Replies
9
Views
2K
Reflection and Refraction in an Elliptical Imaging Mirror
    • Advanced Physics Homework Help
Replies
1
Views
678
Critical angle (symmetry of refraction) confusion
    • Optics
Replies
5
Views
2K
Find Angle of Refraction: Snell's Law Solution
    • Precalculus Mathematics Homework Help
Replies
3
Views
1K
Diffraction grating problem involving Snell's Law
    • Introductory Physics Homework Help
Replies
3
Views
5K

Hot Threads

Recent Insights

Back
Top