Refraction of light

1John says, ‘When hunting a fish under water, you should aim your spear directly at the fish.’ Do you agree? Yes, of course. No, because the fish is actually located somewhere else. No, because size of objects changes when they are put under water.

2When sunlight falls on the water surface, which of the following occur(s)? It is reflected back to the air. It refracts into the water. It is absorbed by water and turned into heat.

air glass Refraction is the bending of light when the light passes from one medium to another. Introduction

air glass Useful words to describe refraction of light normal incident ray angle of refraction angle of incidence refracted ray Introduction

air glass e.g. from air to glass Light is bent towards the normal. incident ray normal refracted ray From a less dense to a denser medium Introduction

air water From a denser to a less dense medium e.g. from water to air Light is bent away from the normal. incident ray refracted ray normal Introduction

MaterialRefractive index Glass1.5 – 1.7 Water1.33 Perspex1.5 Diamond2.42 Refractive indices of some materials Refractive index

air water Example 3 A ray of light passes from air into water. Angle of incidence = 30  What is angle of refraction in water? n water = 

Q1A boy shines a torch under… A boy shines a torch under water as shown. Which one shows the correct path of the light ray? APath X. BPath Y. CPath Z. DAll of them.

Q5Statements:... 1st statement 2nd statement Light is bent towards the normal when it passes from air to glass. Glass has a greater refractive index than air. true? Yes

4Examples of refraction of light aBent chopstick The chopstick appears bent because of refraction

4Examples of refraction of light bShallower in water The depth that the object is actually at is called the real depth. O I real depth Simulation

4Examples of refraction of light cFlickering objects in hot air The object you see through the unstable hot air appears blurred and flickering.

Q1True or false: Light slows… True or false: Light slows down when it enters a material from air. (T/F)

Q2True or false: The refractive… True or false: The refractive index cannot be smaller than 1. (T/F)

Q3True or false: If light travel… True or false: If light travel at the same speed in all materials, refraction would still occur when it passes from air to water. (T/F)

Q4True or false: If the speed of… True or false: If the speed of light in raindrop is equal to that in air, there would be no rainbows. (T/F)

Q5Sketch a ray diagram for the... Sketch a ray diagram for the tip of the chopstick to show why the chopstick looks bent when dipped into water.