Lenses

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What is refraction?
Refraction is when radiation changes direction as it enters a different medium. This is caused by the change in density from one medium to another. This changes the speed of the radiation.
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Explain refraction.
When waves slow down they bend towards the normal. If a wave hits a boundary at 90 degrees it won't change direction but it will slow down. It all depends on the angle of incidence.
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Explain converging lenses.
A converging lens bulges outwards on both sides. They cause parallel rays of light to converge to a focus at the lens focal point.
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Explain diverging lenses.
A diverging lens is concave, so it caves inwards on both sides and causes parallel rays of light to spread out. The focal point of this lens is the point where the rays hitting the lens appear to have come from.
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How do you find the focal point of a diverging lens?
You trace the rays back until they all meet at a point behind the lens. The focal point is always behind the lens which means that it is virtual and therefore produces a virtual image (negative)
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Other cards in this set

Card 2

Front

Explain refraction.

Back

When waves slow down they bend towards the normal. If a wave hits a boundary at 90 degrees it won't change direction but it will slow down. It all depends on the angle of incidence.

Card 3

Front

Explain converging lenses.

Card 4

Front

Explain diverging lenses.

Card 5

Front

How do you find the focal point of a diverging lens?