Two sources of sound A and B produces the wave of 350 Hz, they vibrate in the same phase. The particle P is vibrating under the influence of these two waves, if the amplitudes at the point P produced by the two waves is 0.3 mm and 0.4 mm, then the resultant amplitude of the point P will be when AP ? BP = 25 cm and the velocity of sound is 350 m/sec

• A.            0.7 mm                                   
• B.            0.1 mm
• C.            0.2 mm                                   
• D.            0.5 mm