Same chapter3 marksDifficulty: Medium
A concave mirror of focal length 15 cm forms an image twice the size of the object and real. Find the object distance.
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3 marksDifficulty: Medium
State the lens maker's formula and explain each symbol.
Original Khojo Papers practice question — not from a past board paper.
Answer
1/f = (n − 1)(1/R1 − 1/R2), where f is the focal length of the lens, n the refractive index of its material relative to the surrounding medium, and R1 and R2 the radii of curvature of its two surfaces taken with sign.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
The formula shows that a lens has a different focal length in a medium other than air.
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