JEE Main 2025 Apr 4 Shift 2, Physics Q18: Types and Equations of Waves

JEE Main2025Apr 4, Shift 2Physics

Displacement of a wave is expressed as $x (t) = 5 cos (628 t + \frac{π}{2})$ m. The wavelength of the wave when its velocity is 300 m/s is :

Solution

From the expression, the angular frequency is $ω = 628$ rad/s. Frequency $f = \frac{ω}{2 π} = \frac{628}{2 \times 3.14} = 100$ Hz.

Wave velocity $v = f λ$ , so

$λ = \frac{v}{f} = \frac{300}{100} = 3$ m.

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