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Why does a movie projector have a convex lens?

User ADTC
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2 Answers

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Only convex lenses can generate real images, which can be projected.

User Salvatore Iovene
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Explanation :

A lens can be either convex or concave. The lens used in a movie projector is a convex lens. It is thicker in the middle and thinner in the edges.

The object is placed in between F and 2F. The obtained image in the screen is real, inverted and enlarged.

The film placed into the projector is in the downward direction so that the formed image is the right way up ( as shown in the figure ).

Why does a movie projector have a convex lens?-example-1
User Andrei Dziahel
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