JEE Main 2025 — Waves and Sound Question with Solution
JEE Main 2025 (2 Apr Shift 2)
Question
A sinusoidal wave of wavelength 7.5 cm travels a distance of 1.2 cm along the x -direction in 0.3 sec. The crest is at at and maximum displacement of the wave is 2 cm. Which equation correctly represents this wave ?
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Show full solutionCorrect option: A
Correct answer
A
Step-by-step explanation
$\begin{aligned}
& \mathrm{v}=\frac{\text { distance }}{\text { time }} \\ & \mathrm{v}=\frac{12}{0.3}=4 \mathrm{~cm} / \mathrm{s} \\ & \mathrm{k}=\frac{2 \pi}{\lambda}=\frac{2 \pi}{7.5}=\frac{4 \pi}{15}=0.83 \\ & \mathrm{v}=\frac{\omega}{\mathrm{k}} \Rightarrow \omega=\mathrm{vk}=4 \times \frac{4 \pi}{15}=3.35
\end{aligned}y=A \cos (k x-\omega t)$
& \mathrm{v}=\frac{\text { distance }}{\text { time }} \\ & \mathrm{v}=\frac{12}{0.3}=4 \mathrm{~cm} / \mathrm{s} \\ & \mathrm{k}=\frac{2 \pi}{\lambda}=\frac{2 \pi}{7.5}=\frac{4 \pi}{15}=0.83 \\ & \mathrm{v}=\frac{\omega}{\mathrm{k}} \Rightarrow \omega=\mathrm{vk}=4 \times \frac{4 \pi}{15}=3.35
\end{aligned}y=A \cos (k x-\omega t)$
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This is a previous-year question from JEE Main 2025, covering the Waves and Sound chapter of Physics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.