Two waves of wavelength 50 cm and 51 cm produce 12 beats.  The speed of sound is

Two waves of same frequency and intensity superimpose on each other in opposite phases.  After the superposition, the intensity and frequency of waves will

A star which is emitting radiation at a wavelength of 5000 is approaching the earth with a velocity of 1.50 x10⁶ m/s. The change in wavelength of the radiation as received on the earth is

Which one of the following statements is true ?

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

The phase difference between two waves represented by

where x is expressed in metre and t is expressed in second, is approximately

Standing wavesare produced in a 10 m long stretched string.  If the string vibrates in 5 segments and the wave velocity is 20 m/s, the 5 segments and the wave velocity is 20 m/s, the frequency is

A transverse wave propagating along x-axis is represented by 

Where x is in metre and t is in second.  The speed of the wave is

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

The driver of a car travelling with speed 30 ms^-1 towards a hill sounds a horn of frequency 600 Hz.  If the veocity of sound in air is 330 ms^-1, the frequency of reflected sound as heard by driver is