JEE MainPhysicsWaves and Sound
A plane progressive wave travels in the positive x -direction with an amplitude of 5 cm , frequency of 250 Hz , and wave speed of 500 m/s . Which of the following equations correctly represents this wave? (Assume the initial phase is zero)
Options
- Ay = 5 (250 t - 2 x) cm
- By = 5 (500 t + x) cm
- Cy = 5 ( t - 500 x) cm
- Dy = 5 (500 t - x) cm
Correct answer
D. y = 5 (500 t - x) cm
Step-by-step solution
The angular frequency is given by = 2 f = 2 250 = 500 rad/s . The wavelength is = v f = 500 250 = 2 m . The wave number is k = 2 = 2 2 = rad/m . Since the wave is traveling in the positive x -direction, the phase term must be of the form ( t - kx) . Therefore, the equation of the wave is y = A ( t - kx) = 5 (500 t - x) cm . Answer: y = 5 (500 t - x) cm