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QJEEM23Phb44d: JEE Main 2023 Physics - Class 11 JEEM23Phb44d Solution: The equation of wave is given by where and are in and in . The…

The equation of wave is given by

Y=10−2sin⁡2π(160t−0.5x+π/4)\mathrm{Y}=10^{-2} \sin 2 \pi(160 t-0.5 x+\pi / 4)

where xx and YY are in m\mathrm{m} and t\mathrm{t} in ss . The speed of the wave is ________ km h−1\mathrm{km} ~\mathrm{h}^{-1} .

Step-by-Step Verified Solution

Given the wave equation:

Y=10−2sin⁡2π(160t−0.5x+π/4)Y = 10^{-2} \sin 2 \pi(160t - 0.5x + \pi/4)

Comparing this equation with the general form:

Y=Asin⁡(2π(ft−kx+ϕ))Y = A \sin(2\pi(ft - kx + \phi))

We can identify the wave number k=0.5 m−1k = 0.5\,\mathrm{m}^{-1} and the frequency f=160 Hzf = 160\,\mathrm{Hz} . The wave speed vv can be found using the relationship between wave number, wave speed, and frequency:

v=ωk=2πf2πkv = \frac{\omega}{k} = \frac{2\pi f}{2\pi k}

Now, we can calculate the wave speed:

v=2π×1602π×0.5=1600.5 m/sv = \frac{2\pi \times 160}{2\pi \times 0.5} = \frac{160}{0.5}\,\mathrm{m/s}

v=320 m/sv = 320\,\mathrm{m/s}

Now, we need to convert the wave speed from meters per second to kilometers per hour:

v=320ms×1 km1000 m×3600 s1 hv = 320 \frac{\mathrm{m}}{\mathrm{s}} \times \frac{1\,\mathrm{km}}{1000\,\mathrm{m}} \times \frac{3600\,\mathrm{s}}{1\,\mathrm{h}}

v=320×11000×3600 km/hv = 320 \times \frac{1}{1000} \times 3600\,\mathrm{km/h}

v=1152 km/hv = 1152\,\mathrm{km/h}

So, the speed of the wave is 1152 km/h1152\,\mathrm{km/h} .

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