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

Each of the two strings of length 51.6 cm and 49.1 cm are tensioned separately by 20 N force.  Mass per unit length of both the strings is same and equal to 1 gm^-1.  When both the strings vibrate simultaneously the number of beats is  

Equations of two progressive waves are given by 

If amplitude and time period of resultant wave are same as that of both the waves, then 

A wave enters to water from air.  In air frequency, wavelength, intensity and velocity are

In water the corresponding quantities are 

The wave described by

where x and y are in metre and t in second, is a wave travelling along the

Velocity of sound waves in air is 330 m/s.  For a particular sound wave in air, path difference of 40 cm is equivalent to phase difference of 

Two periodic waves of intensities I₁ and  I₂ pass through a region at the same time in the same direction.  The sum of the maximum and minimum intensities is

In a sinusoidal wave, the time required for a particular point, to move from maximum displacement to zero displacement is 0.170 s.  The frequency of the wave is

The frequency of sinusoidal wave, 0.40 cos (2000t +0.80) would be 

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