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Friday, 9 October

JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumApplication

JEE Main 3 August 2021, Shift 2, Physics Q2

Question 2 of 90 in this shift, Physics question 2 of 30, Section A.

A block of mass m rigidly attached with a spring of spring constant KK, is compressed through a small distance A. If the block is now released, the time taken by the block in going from P to Q will be

The figure, in words

Block of mass m attached to a spring of constant K (fixed to wall at left), compressed by distance A to point P; O is the natural-length position; Q is at distance A/2 beyond O on the other side.
  1. (1)34πmK\frac{3}{4\pi}\sqrt{\frac{m}{K}}
  2. (2)2π3mK\frac{2\pi}{3}\sqrt{\frac{m}{K}}Official answer
  3. (3)3π4mK\frac{3\pi}{4}\sqrt{\frac{m}{K}}
  4. (4)3π4Km\frac{3\pi}{4}\sqrt{\frac{K}{m}}

Official answer

Option 2

NTA final key.

Chapter
Oscillations
Topic
SHM Equations
Idea tested
Phasor Diagram Technique

Same idea in other shifts

Asked 5× in all
  1. 6 Apr 2026, Shift 1 · Q37A particle is executing simple harmonic motion. Its amplitude is AA and time period is 5 sec. The time required by it to move from x=Ax=A…EasySingle correct
  2. 8 Apr 2023, Shift 2 · Q32For particle PP revolving round the centre OO with radius of circular path rr and angular velocity ω\omega, as shown in below figure,…MediumSingle correctHas a figure
  3. 3 Aug 2021, Shift 2 · Q1A particle is executing simple harmonic motion with time period TT. What is the time taken by the particle to go directly to…EasySingle correct
  4. 18 Mar 2021, Shift 1 · Q25A particle performs simple harmonic motion with a period of 2 second. The time taken by the particle to cover a displacement equal to half…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. 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.