Homework Help

# Light is passing through a transparent material at an angle of 63 degrees.  The...

Valedictorian

• Up
• 0
• Down

Light is passing through a transparent material at an angle of 63 degrees.  The material has an index of refraction of 1.6.  At what angle will the light pass into the air?

Posted by lkehoe on April 24, 2013 at 11:15 PM via web and tagged with angle, index of refraction, light, material, optics, physics, science, transparent

College Teacher

(Level 2) Distinguished Educator

• Up
• 1
• Down

When a beam of light passes from one medium to another the beam bends if the two mediums do not have the same refractive index.

If the angle of incidence is A and the angle of refraction is B, the two are related as (sin A)/(sin B) = (n2)/(n1) where n1 is the refractive index of the first medium and n2 is the refractive index of the second.

In the problem, the angle of incidence A is 63 degrees and the refractive index of the material is 1.6. The refractive index of air is 1. If B is the angle of refraction, sin 63/sin B = 1/1.6

=> sin B = 1.6*sin 63

=> sin B = 1.425

Is is seen that sin B > 1. This indicates that the beam of light does not pass into the air. The beam of light undergoes total internal reflection.

Posted by justaguide on May 19, 2013 at 5:56 AM (Answer #1)

High School Teacher

• Up
• 0
• Down

Snell's Law:

n_1sin(\theta_1)=n_2sin(\theta_2)

let n_1 = 1.0 (air) and n_2 = 1.6

So, \theta_1 = 63^o

Solve for \theta_2

\theta_2 = sin^(-1)(n_1/n_2*sin(\theta_1))

\theta_2 =sin^(-1)(1.0/1.6*sin(63^o))

:. \theta_2 = 33.8^o

Posted by quirozd on April 25, 2013 at 1:44 AM (Answer #1)

See all »