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प्रश्न
Fig shows a lens as a combination of a glass block and two prisms.

(i) Name the lens formed by the combination.
(ii) what is the XX' called?
(iii) Complete the ray diagram and show the path of the incident ray PQ after passing through the lens.
(iv) The final emergent ray will either meet XX' at a point or appear to come from a point on XX'. what is the point called?
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उत्तर
(i) Convex lens
(ii) The line XX' is calledf the principal axis.
(iii)

(iv) The final emergent ray will meet XX' at a point called its principal focus of the lens.
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