An observer is standing between two vehicles, each moving with a speed 4 ms–1. One vehicle is approaching him and the other going away from him. If each vehicle is blowing a horn of frequency 240 Hz and the speed of sound is 320 ms–1, the number of beats per second will be


Correct option is



The apparent frequencies of the two sounds are





Two waves of wavelength 2 m and 2.02 m moving with the same speed superpose to produce 2 beats per second. The speed of each wave is


The potential energy of a particle executing simple harmonic motion at a distance x from the equilibrium position is proportional to



Two travelling waves



are superposed on a string. The distance between adjacent nodes is


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


At a certain instant a stationary transverse wave is found to have maximum kinetic energy. The appearance of the string at that instant is a



The displacement y of a particle executing simple harmonic motion is given by 


The expression may be considered to be a result of the superposition of how many simple harmonic motions?


A wave of frequency 100 Hz is sent along a string towards a fixed end. When this wave travels back after reflection, a node is formed at a distance of 10 cm from the fixed end of the string. The speed of the incident (or reflected) wave is


A particle starts simple harmonic motion from the mean position O as shown in the figure. Its amplitude is A and its time period is T. At a certain instant, its speed is half its maximum speed. At this instant, the displacement x is




The wave equation is 


Where tx and y are in second, metre and centimeter respectively. The speed of the wave is


A spring is extended by a length l, the according to Hooke’s law