AP® Physics 1 & 2

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Refraction in Unknown Material


Consider a beam of light traveling through water toward an unknown material. The beam of light strikes the surface, as shown in the image, at an incidence angle of ${ 52.1}^{ \circ }$. Although the material is unknown, measurements show that light travels at a speed five times less the speed of light in water.

Does the beam of light refract (cross the boundary) in the unknown material?

Created for Albert.io. Copyright 2016. All rights reserved.


Yes, by an angle of ${ 11.5 }^{ \circ }$.


No, the critical angle is ${ 11.5 }^{ \circ }$ and the incidence angle is greater than the critical angle. Thus total internal reflection occurs and no light refracts.


Yes, by an angle of ${ 90.1 }^{ \circ }$.


Yes, by an angle of ${ 9.1 }^{ \circ }$.