Total Internal Reflection Grade 11 Content.pptx

Total internal reflection. Angle of incidence. Real life examples

1. Total Internal Reflection Grade 11

2. Recap- Refraction •Light bends when it moves from one medium to another. •Bends towards the normal when entering a denser medium. •Bends away from the normal when entering a rarer medium.

3. Test your knowledge -1 What happens to light when it passes from air into water? light bends towards the normal Light bends away from the normal Light continues in a straight line

4. Test your knowledge - 2 Why do some objects underwater, like a straw in a glass, appear bent or broken when viewed from above?

5. Critical angle the angle of incidence in the optically denser medium for which the angle of refraction in the optically less dense medium is 90 Occurs only when light moves from a denser to a rarer medium.

6. Total internal reflection total internal reflection is when the refracted ray does not emerge from the medium, but is reflected back into the medium. Conditions Light must travel from an optically denser medium to an optically less dense medium. The angle of incidence in the optically denser medium must be greater than the critical angle.

7. Test your knowledge What two conditions must be met for total internal reflection to occur? Why does light bend away from the normal when it travels from water into air? If a swimmer underwater looks up at an angle greater than the critical angle, what will they see? Explain.