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Saturday, 31 October

JEE Main 2020 · PhysicsMultiple choiceDiagram basedMediumData or graph

JEE Main 8 January 2020, Shift 2, Physics Q16

Question 16 of 75 in this shift, Physics question 16 of 25, Section A.

An object is gradually moving away from the focal point of a concave mirror along the axis of the mirror. The graphical representation of the magnitude of linear magnification (m) versus distance of the object from the mirror (xx) is correctly given by (Graphs are drawn schematically and are not to scale)

The figure, in words

Each of the four options is a graph with axes labelled m and x, x-axis marks f and 2f, m-axis mark 1; see option text.
  1. (1)[figure: graph of m (vertical) against x (horizontal) with marks f and 2f on the x axis and 1 on the m axis; curve starts at the origin and rises, curving upward]
  2. (2)[figure: graph of m against x with marks f, 2f on x axis and 1 on m axis; decreasing curve starting high near the m axis (above 1) and flattening toward the right]
  3. (3)[figure: graph of m against x with marks f, 2f on x axis and 1 on m axis; dotted horizontal line from m=1 to a vertical line at 2f; decreasing curve starting high, passing through the corner at (2f, 1) and flattening to the right]Official answer
  4. (4)[figure: graph of m against x with marks f, 2f on x axis and 1 on m axis; curve starts at the origin, rises and flattens to a plateau just above 1]

Official answer

Option 3

NTA final key (Jan 2020).

Chapter
Ray Optics and Optical Instruments
Topic
Spherical Mirrors
Idea tested
Magnification vs Object Distance Graph

Same topic in other shifts

All Spherical Mirrors questions
  1. 4 Apr 2026, Shift 1 · Q39A 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…MediumDiagram basedHas a figure
  2. 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
  3. 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
  4. 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
  5. 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
  6. 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

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.