# P3 Lenses and Mirrors

Summaries of Concave and Convex Mirrors and Lenses!

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• Created by: Northy
• Created on: 26-05-11 14:11

## Concave (Converging) Mirrors

Ray 1: from the top of the object, parallel to the pricipal axis and it is reflected through the focal point

Ray 2: from through the focal point and it is reflected parallel to the principall axis

If the object is beyond the focal point:

Where the two rays meet is the location of the image.

The image is: inverted, real and smaller (depending on the distance from the object to the mirror)

If the object is between the focal point and the mirrior:

From the point of reflection continue both rays as sight lines through the mirror, where these two intersect is the location of the image.

The image is: upright, virtual and bigger.

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## Convex (Diverging) Mirrrors

Ray 1:from the top of the object, parallel to the principal axis and it is reflected through the focal point on the other side of the mirror as the object.

Ray 2: from through the opposite side focal point and it is reflected parallel to the principal axis.

From the point of reflection continue both rays as sight lines through the mirror, where these two intersect is the location of the image.

The image is: upright, virtual and smaller.

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## Concave (Diverging) Lenses

Ray 1: from the top of the object, parallel to the pricipal axis and it is refracted from the focal point (same side as object).

Ray 2: from the top of the object straight through the middle of the lens with no refraction.

From the point of refraction continue ray 1 as a sight line, back through the lens meeting at the focal point (same side as object).

Where Ray 1's sight line and ray 2 meet is the image's location.

The image is: upright, virtual, smaller and on the same side of the lens as the object.

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## Convex (Converging) Lenses

Ray 1: from the top of the object, parallel to the pricipal axis and it is refracted through the opposite side's focal point.

Ray 2: from the top of the object straight through the middle of the lens with no refraction.

If the distance from the object to the lense is bigger than the distance from the lens to the focus point:

Where these two rays meet is the image location

The image is inverted, real and a different size.

If the distance is less:

From the point of refraction continue both rays as sight lines back through the lens, where these two sight lines meet is the location of the image.

The image is: upright, virtual, bigger and on the same side as the object.

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