Two coherent narrow slits emitting sound of wavelength λ in the same phase are placed parallel to each other at a small separation of 2λ. The sound is detected by moving a detector on the screen ∑ at a distance D(>>λ) from the slit S₁ as shown in figure (16-E6). Find the distance x such that the intensity at P is equal to the intensity at O.

Two speakers S₁ and S₂, driven by the same amplifier, are placed at y = 1.0 m and y = - 1.0 m (figure 16-E4). The speakers vibrate in phase at 600 Hz. A man stands at a point on the X-axis at a very large distance from the origin and starts moving parallel to the Y-axis. The speed of sound in air is 330 m/s. (a) At what angle θ will the intensity of sound drop to a minimum for the first time? (b) At what angle will he hear a maximum of sound intensity for the first time? (C) If he continues to walk along the line, how many more maxima can he hear?

Three sources of sound S₁, S₂ and S₃ of equal intensity are placed in a straight line with S₁S₂ = S₂S₃ (figure 16-E5). At a point P, far away from the sources, the wave coming from S2 is 120^o ahead in phase of that from S¹. Also, the wave coming from S³ is 120^o ahead of that from S₂. What would be the resultant intensity of sound at P?

Figure (16-E7) shows two coherent sources S₁ and S₂ which emit sound of wavelength λ in phase. The separation between the sources is 3λ. A circular wire of large radius is placed in such a way that S₁S₂ lies in its plane and the middle point of S₁S₂ is at the centre of the wire. Find the angular positions θ on the wire for which constructive takes place.

Two sources of sound S₁ and S₂ vibrate at same frequency and are in phase (figure 16-E8). The intensity of sound detected at a point P as shown in the figure is I₀. (a) If θ equals 45°, what will be the intensity of sound detected at this point if one of the Sources is switched off? (b) What will be the answer of the previous part if θ = 60^o?