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Lenses for GSEB: 10 solved questions

Real GSEB paper questions on lenses, part of ray optics and optical instruments. Each opens with the options, the correct answer and a step-by-step solution. Papers run from 2015 to 2023. No sign-in needed to read them.

What this topic asks

• Lens maker's formula and power — 7 questions
• Lens formula and magnification — 1 question
• Combinations and silvered lenses — 1 question
• Units and dimensions — 1 question

All 10 questions with solutions

• The radii of curvature of both the sides of a convex lens are 15 cm and the refractive index of the material… GSEB Board July 2015
• The focal length of a thin lens made from the material of refractive index 1.5 is 20 cm. When it is placed in… GSEB Board July 2016
• The focal length of an equiconvex lens in air is equal to either of its radii of curvature. The refractive in… GSEB Board July 2016
• For a thin convex lens, when the height of the object is double that of its image, its object distance is equ… GSEB Board July 2017
• A magician during a show makes a glass lens with n=1.47 disappear in a trough of liquid. What is the refracti… GSEB Board March 2020
• A magician during a show makes a glass lens with n = 1.47 disappear in a trough of liquid. The refractive ind… GSEB Board August 2020
• If the focal length of a converging lens is 0.25 m then the power of this lens is dioptre. GSEB Board July 2021
• A magician during a show makes a glass lens with refractive index n=1.5 disappear in a trough of liquid. The… GSEB Board March 2022
• What is the focal length of the combination of a convex lens of focal length 20 cm in contact with a concave… GSEB Board July 2023
• Dimensional formula for power of a lens is . GSEB Board August 2020