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JEE Main 4 September 2020, Shift 2, Physics Q24

Question 24 of 75 in this shift, Physics question 24 of 25.

The distance between an object and a screen is 100 cm. A lens can produce real image of the object on the screen for two different positions between the screen and the object. The distance between these two positions is 40 cm. If the power of the lens is close to

\left(\frac{N}{100}\right)

D where N is an integer, the value of N is __________.

Official answer

5.00

NTA final key (Sep 2020).

Chapter: Ray Optics and Optical Instruments
Topic: Lens Maker's Formula
Idea tested: Displacement Method

Same topic in other shifts

All Lens Maker's Formula questions

2 Apr 2026, Shift 2 · Q49If sunlight is focused on a paper using convex lens, it starts burning the paper in shortest time when the lens is kept at 30 cm above the…EasyNumerical value
4 Apr 2026, Shift 2 · Q41A convex lens is made from glass material having refractive index of 1.4 with same radius of curvature on both sides. The ratio of its…EasySingle correct
5 Apr 2026, Shift 2 · Q40A thin convex lens and a thin concave lens are kept in contact and are co-axial. Which of the following statements is correct for this…EasySingle correct
5 Apr 2026, Shift 2 · Q41An object $AB$ is placed 15 cm on the left of a convex lens $P$ of focal length 10 cm. Another convex lens $Q$ is now placed 15 cm right…MediumSingle correct
8 Apr 2026, Shift 2 · Q30A thin biconvex lens is prepared from the glass ( $\mu = 1.5$ ) both curved surfaces of which have equal radii of 20 cm each. Left side…MediumSingle correct
2 Apr 2025, Shift 1 · Q41A slanted object AB is placed on one side of convex lens as shown in the diagram. The image is formed on the opposite side. Angle made by…HardDiagram basedHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.