Two sound waves of frequencies and reach an observer simultaneously

PHYSICS · Single correct · CBSE · Physics · Waves · Waves

Problem

Two sound waves of frequencies

256\,\text{Hz}

and

262\,\text{Hz}

reach an observer simultaneously. How many complete beats will the observer hear in a time interval of

1.8\,\text{s}

? (a) 12 (b) 11 (c) 10 (d) 6