When two waves of the same amplitude $a$ and the same frequency $f$ superimpose,the total intensity is proportional to which of the following?

Two pulses travel in mutually opposite directions in a string with a speed of $2.5 \ cm/s$ as shown in the figure. Initially,the pulses are $10 \ cm$ apart. What will be the state of the string after two seconds?

Two waves of the same frequency and same amplitude $a$ are superimposed. If the resultant amplitude is also $a$,what is the phase difference between the two waves?

Three harmonic waves having equal frequency $v$ and same intensity $I_{0}$,have phase angles $0, \frac{\pi}{4}$ and $-\frac{\pi}{4}$ respectively. When they are superimposed,the intensity of the resultant wave is close to

Sound waves are passing through two routes—one in a straight path and the other along a semicircular path of radius $r$—and are again combined into one pipe and superposed as shown in the figure. If the velocity of sound waves in the pipe is $v$, then frequencies of resultant waves of maximum amplitude will be integral multiples of

Two identical waves $1$ and $2$,each of intensity $I_0$,are superimposed. The resulting intensity is: