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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceSingle correctMediumApplication

JEE Main 3 August 2021, Shift 1, Physics Q9

Question 9 of 90 in this shift, Physics question 9 of 30, Section A.

A sinusoidal wave f1(t)=3 sin⁡ ω tf_1(t) = 3\ \sin\ \omega\, t is superposed on another periodic wave f2(t)f_2(t) which is also oscillating with the same frequency. If the resultant wave is a sinusoidal wave, which is out of phase with f1(t)f_1(t) by 53.1° ; then the wave f2(t)f_2(t) would be - [Given tan 53.1° = 1.33]
  1. (1)f2(t)=3 sin⁡ (ω t)f_2(t) = 3\ \sin\ (\omega\, t)
  2. (2)f2(t)=4 sin⁡ (ω t+53.1°)f_2(t) = 4\ \sin\ (\omega\, t + 53.1°)
  3. (3)f2(t)=3 cos⁡ (ω t−53.1°)f_2(t) = 3\ \cos\ (\omega\, t - 53.1°)
  4. (4)f2(t)=4 cos⁡ (ω t)f_2(t) = 4\ \cos\ (\omega\, t)Official answer

Official answer

Option 4

NTA final key.

Chapter
Waves
Topic
SHM Equations
Idea tested
Collinear Superposition of SHMs

Same idea in other shifts

Asked 6× in all
  1. 2 Apr 2025, Shift 1 · Q33A particle is subjected to two simple harmonic motions as : x1=7sin⁡5tx_1=\sqrt{7}\sin5t cm and x2=27sin⁡(5t+π3)x_2=2\sqrt{7}\sin\left(5t+\frac{\pi}{3}\right)…MediumSingle correct
  2. 10 Apr 2023, Shift 2 · Q32For a periodic motion represented by the equation y=sin⁡ωt+cos⁡ωty = \sin \omega t + \cos \omega t the amplitude of the motion isEasySingle correct
  3. 25 Jul 2022, Shift 2 · Q57Two waves executing simple harmonic motions travelling in the same direction with same amplitude and frequency are superimposed. The…EasyNumerical value
  4. 26 Aug 2021, Shift 2 · Q24Two simple harmonic motions are represented by the equations x1=5sin⁡(2πt+π4)x_1=5\sin\left(2\pi t+\frac{\pi}{4}\right) and…EasyNumerical value
  5. 27 Aug 2021, Shift 2 · Q27Two simple harmonic motion, are represented by the equations y1=10sin⁡(3πt+π3)y_1=10\sin\left(3\pi t+\frac{\pi}{3}\right)…EasyNumerical 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.