A simple harmonic progressive wave is represented by $y = A \sin(120\pi t + 3x)$. The distance between two points on the wave at a phase difference of $\dfrac{\pi}{3}$ radian is

A pipe open at both ends has a fundamental frequency 'f' in air. The pipe is dipped in water, so that $\dfrac{2}{3}^{rd}$ length of pipe is in water, Now the fundamental frequency of the air column is

To increase the frequency of transverse oscillations of a stretched string by 40%, the tension must be increased by

When open pipe is closed from one end then second overtone of closed pipe is higher in frequency by 100 Hz than first overtone of open pipe. The fundamental frequency of open end pipe will be (Neglect end correction)