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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 26 August 2021, Shift 1, Physics Q8

Question 8 of 90 in this shift, Physics question 8 of 30, Section A.

Car B overtakes another car A at a relative speed of 40 ms−140\ \mathrm{ms^{-1}}. How fast will the image of car B appear to move in the mirror of focal length 10 cm fitted in car A, when the car B is 1.9 m away from the car A ?
  1. (1)0.1 ms−10.1\ \mathrm{ms^{-1}}Official answer
  2. (2)0.2 ms−10.2\ \mathrm{ms^{-1}}
  3. (3)40 ms−140\ \mathrm{ms^{-1}}
  4. (4)4 ms−14\ \mathrm{ms^{-1}}

Official answer

Option 1

NTA final key.

Chapter
Ray Optics and Optical Instruments
Topic
Spherical Mirrors
Idea tested
Image Velocity (Axial Motion)

Same idea in other shifts

Asked 3× in all
  1. 10 Apr 2023, Shift 1 · Q47An object is placed at a distance of 12 cm in front of a plane mirror. The virtual and erect image is formed by the mirror. Now the mirror…EasySingle correct
  2. 3 Sep 2020, Shift 2 · Q25When an object is kept at a distance of 30 cm from a concave mirror, the image is formed at a distance of 10 cm from the mirror. If the…MediumNumerical value

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.