Physics Question from JEE Main 2026 · 22 January, Shift 1

Two loudspeakers ($L_1$ and $L_2$) are placed with a separation of $10 \, \text{m}$, as shown in the figure. Both speakers are fed with an audio input signal of the same frequency with constant volume. A voice recorder, initially at point $A$, at equidistance to both loudspeakers, is moved by $25 \, \text{m}$ along the line $AB$ while monitoring the audio signal. The measured signal was found to undergo $10$ cycles of minima and maxima during the movement. The frequency of the input signal is _____ Hz.

(Speed of sound in air is $324 \, \text{m/s}$ and $\sqrt{5} = 2.23$)