PYQ NEET- Waves Equation Sinusoidal & Speed Of Waves

• 2018: The frequency of the whistle as heard by a person standing near the track is

f' = f * (v + u)/(v - u)

where f is the original frequency of the whistle, v is the speed of sound in air, and u is the speed of the train.

In this case, v = 340 m/s, u = 20 m/s, and f = 500 Hz. Substituting these values into the equation, we get f’ = 505 Hz.

• 2017: The minimum distance between two consecutive points on the string, having the same phase is called the wavelength.

λ = v/f

where λ is the wavelength, v is the speed of the wave, and f is the frequency.

In this case, v = 50 cm/s and f = 20 Hz. Substituting these values into the equation, we get λ = 2.5 cm.

• 2016: The speed of sound in hydrogen at NTP will be

v = √(γRT)