Learn

Saturday, 31 October

JEE Main 2021 · PhysicsNumerical answerNumerical valueHardMulti-step

JEE Main 26 August 2021, Shift 2, Physics Q27

Question 27 of 90 in this shift, Physics question 27 of 30, Section B.

An object is placed at a distance of 12 cm from a convex lens. A convex mirror of focal length 15 cm is placed on other side of lens at 8 cm as shown in the figure. Image of object coincides with the object. When the convex mirror is removed, a real and inverted image is formed at a position. The distance of the image from the object will be __________(cm).

The figure, in words

Horizontal axis with a vertical line at the left labelled 'Image' (upper) and 'Object' (lower) with a cross on the axis; a convex lens 12 cm to its right (distance marked 12 cm); a curved mirror with hatched back 8 cm further right (distance marked 8 cm); at the far right a vertical dashed arrow pointing down to the axis, labelled 'Image in the absence of mirror'.

Official answer

50

NTA final key.

Chapter
Ray Optics and Optical Instruments
Topic
Lens Maker's Formula
Idea tested
Lens and Curved Mirror Coincidence

Same topic in other shifts

All Lens Maker's Formula questions
  1. 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
  2. 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
  3. 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
  4. 5 Apr 2026, Shift 2 · Q41An object ABAB is placed 15 cm on the left of a convex lens PP of focal length 10 cm. Another convex lens QQ is now placed 15 cm right…MediumSingle correct
  5. 8 Apr 2026, Shift 2 · Q30A thin biconvex lens is prepared from the glass (μ=1.5\mu = 1.5) both curved surfaces of which have equal radii of 20 cm each. Left side…MediumSingle correct
  6. 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. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.