The wavelength of two waves are 40 and $$42 \mathrm{~cm}$$ respectively. If the temperature of the room is $$20^{\circ} \mathrm{C}$$ then what will be the number of beats produced per second by these waves. When the speed of sound at $$0^{\circ} \mathrm{C}$$ is $$332 \mathrm{~m} / \mathrm{s}$$ ?

When a string is divided into four segments of $$l_1, l_2, l_3$$ and $$l_4$$. The fundamental frequencies of these three segments are $$v_1, v_2, v_3$$ and $$v_4$$, respectively. The original fundamental frequency $$(v)$$ of the string is

In a resonance coloum first and second resonance are obtained at depths 24 cm and 78 cm the third resonance will be obtained at depth.

A submarine A travelling at 17 m/s is being chased along the line of its velocity by another submarine B travelling at 34 m/s. B sends a sonar signal of 600 Hz to detect A and receives a reflected sound of frequency $$\nu$$. The of $$\nu$$ is

[Speed of sound in water = 1500 ms^$$-$$1]