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JEE MAIN 2025
02-04-2025 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 P is at $x=0$ at $t=0 \mathrm{sec}$ and maximum displacement of the wave is 2 cm . Which equation correctly represents this wave?
Select the correct option:
A
$y=2 \cos (0.83 x-3.35 t) \mathrm{cm}$
B
$y=2 \cos (0.13 x-0.5 t) \mathrm{cm}$
C
$y=2 \sin (0.83 x-3.5 t) \mathrm{cm}$
D
$y=2 \cos (3.35 x-0.83 t) \mathrm{cm}$
✓ Correct! Well done.
✗ Incorrect. Try again or view the solution.
Solution
$v=\frac{\text { distance }}{\text { time }}$
$v=\frac{12}{0.3}=4 \mathrm{~cm} / \mathrm{s}$
$k=\frac{2 \pi}{\lambda}=\frac{2 \pi}{7.5}=\frac{4 \pi}{15}=0.83$
$v=\frac{\omega}{k} \Rightarrow \omega=v k=4 \times \frac{4 \pi}{15}=3.35$
So $y=A \cos (k x-\omega t)$
Question Tags
JEE Main
Physics
Easy
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