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Saturday, 10 October

JEE Main 2026 · PhysicsMultiple choiceDiagram basedMediumMulti-step

JEE Main 4 April 2026, Shift 1, Physics Q39

Question 39 of 75 in this shift, Physics question 14 of 25, Section A.

A rod of length 1010 cm lies along the principle axis of a concave mirror of focal length 1010 cm as shown in figure. The length of the image is ______ cm.

The figure, in words

Concave mirror with principal axis drawn horizontally; a hatched rod of length 10 cm lies on the axis to the left of the mirror, its right (near) end at a distance of 20 cm from the mirror pole (marked 20 cm).
  1. (1)2.52.5
  2. (2)55Official answer
  3. (3)7.57.5
  4. (4)77

Official answer

Option 2

NTA final key.

Chapter
Ray Optics and Optical Instruments
Topic
Spherical Mirrors
Idea tested
Longitudinal Magnification

Same topic in other shifts

All Spherical Mirrors questions
  1. 6 Apr 2026, Shift 2 · Q50A concave mirror of focal length 10 cm forms an image which is double the size of object when the object is placed at two different…MediumNumerical value
  2. 2 Apr 2025, Shift 2 · Q36Two identical objects are placed in front of convex mirror and concave mirror having same radii of curvature of 12 cm, at same distance of…MediumSingle correct
  3. 4 Apr 2025, Shift 2 · Q39A finite size object is placed normal to the principal axis at a distance of 30 cm from a convex mirror of focal length 30 cm. A plane…MediumSingle correct
  4. 7 Apr 2025, Shift 2 · Q40A mirror is used to produce an image with magnification of 14\frac{1}{4}. If the distance between object and its image is 40 cm, then the…MediumSingle correct
  5. 29 Jan 2024, Shift 1 · Q49A convex mirror of radius of curvature 30 cm forms an image that is half the size of the object. The object distance is :EasySingle correct
  6. 2 Sep 2020, Shift 1 · Q16A spherical mirror is obtained as shown in the figure from a hollow glass sphere. If an object is positioned in front of the mirror, what…MediumDiagram 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 42 of the 174 JEE Main shifts held from 2017 to 2026.