Figure shows ray AB that has passed through a divergent lens. Construct the path of the ray up to the lens if the position of its foci is known

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Figure shows ray AB that has passed through a divergent lens. Construct the path of the ray up to the lens if the position of its foci is known

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Given AB is the ray that passes through a diverging lens.

F is the focus of the lens.

If AB ray is extended backward it seems to be passing through focal point (F).

This is possible only when incident ray is parallel to the principal axis.