# Reflection & Refraction

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Category: Education

## Presentation Description

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## Presentation Transcript

### Slide 1:

The King David High School Science Department Reflection and Refraction By Mr Jones

### Reflection:

Reflection For light reflecting off a plane mirror (flat, smooth, shiny): Mirror Incident Ray Reflected Ray Normal Angle of reflection (r) r i The normal is a line drawn at right angles (perpendicular) to the surface. Angle of incidence ( i ) =

### Reflection:

Reflection For light reflecting off a plane mirror (flat, smooth, shiny): Mirror Angle of reflection (r) Angle of incidence ( i ) =

### Refraction:

Refraction Air Perspex Incident Ray Emergent Ray Normal Normal Refracted Ray

### Refraction:

Refraction As light passes from a less optically dense material into a more optically dense material it moves towards the normal. As light passes from a more optically dense material into a less optically dense material it moves away from the normal. Less optically dense More optically dense Incident Ray Normal Less optically dense More optically dense Emergent Ray Normal

### Total Internal Reflection:

Total Internal Reflection Incident Ray Refracted Ray Reflected Ray When the angle of incidence is small (less than 42°) most of the light emerges from the Perspex and is refracted away from the normal. A tiny amount of light is reflected at the interface. i <42°

### Total Internal Reflection:

Total Internal Reflection Incident Ray When the angle of incidence is 42° most of the light is refracted at 90° from the normal (along the interface). Some light is reflected at the interface. 42° is described as the critical angle. 42° 90°

### Total Internal Reflection:

Total Internal Reflection Incident Ray Reflected Ray When the angle of incidence is greater than 42° no refraction takes place. All of the light is reflected. This is known as total internal reflection. i >42°

### Total Internal Reflection:

Total Internal Reflection