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Question
When does a ray of light falling on a lens pass through it undeviated?
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Solution
A ray of light falling on the lens passes through it undeviated when it passes through the optical centre.
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In figure, (a) and (b), F1 and F2 are the two foci of thin lenses and AB is the incident ray. Complete the diagram to show the path of the ray AB after refraction through each lens.
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