Download - Refraction is the bending of a wave when it enters a substance where its speed is different
• Refraction is the bending of a wave when it enters a substance where its speed is different.
airglass
normal
incident ray
angle of refraction
angle of incidence
refracted ray
air
glass
• e.g. from air to glass
• Light is bent towards the normal.
incident raynormal
refracted ray
From a less dense to a denser substance
air
water
From a denser to a less dense substance• e.g. from water to air
• Light is bent away from the normal.
incident ray
refracted ray
normal
• When light hits a different surface than what it had been traveling in, some light is reflected and some is refracted (bent).
• Light passes through substances at different speeds, causing it to bend.
• The index of refraction measures the speed at which light moves through the substance.
• The more that light is bent (refracted) as it passes through a substance, the higher the index of refraction of the substance.
Stirring Rod in WaterWater n = 1.3330Pyrex n = 1.470
Stirring Rod in OilOil n = 1.474Pyrex n = 1.470
Refraction of Light by Water• The index of
refracton for water is 4/3, meaning that light travels 3/4 as fast in water as it does in vacuum.
Bent chopstick
Water Line
Air
A
B
C
Examples of refraction of light Shallower in water
O
Ireal depth
‘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.
A boy shines a torch under water as shown.Which one shows the correct path of the light ray?