A vehicle, with a horn of frequency n is moving with a velocity of 30 m/s in a direction perpendicular to the straight line joining the observer and the vehicle. The observer perceives the sound to have a frequency n + n₁.Then n1 is equal to : ( the sound velocity in air is 300 m/s)

Two waves are said to be coherent, if they have:

If the amplitude of sound is doubled and the frequency reduced to one-fourth, the intensity of sound at the same point will:

Equations of two progressive waves are given by y1 = a sin (ωt + ø₂). If amplitude and time period of resultant wave are same as that of both the waves, then (ø₁ - ø₂) is:

A cylindrical resonance tube open at both ends, has a fundamental frequency ƒ, in air. If half of the length is dipped vertically in water, the fundamental frequency of the air column will be:

A car is moving towards a high cliff. The car driver sounds a horn of frequency ƒ. The reflected sound heard by the driver has a frequency 2ƒ. If v be the velocity of sound, then the velocity of the car, in the same velocity units, will be:

Two waves are approaching each other with a velocity of 20 m/s and frequency n. The distance between two consecutive nodes is:

A whistle revolves in a circle with angular velocity ω = 20 rad/s using a string of length 50 cm. If the actual frequency of sound from the whistle is 385 Hz, then minimum frequency heard by the observer far away from the centre is: (velocity of sound v = 340 m/s)

A 5.5 m length of string has a mass of 0.035 kg. If the tension in the string is 77 N, the speed of a wave on the string is:

A star which is emitting radiation at a wavelength of 5000Å is approaching the earth with a velocity of 1.50 × 10⁶ m/s. The change in wavelength of the radiation as received on the earth is: