Question

# A wire of length 80 cm under some tension produces a sound of frequency 256 Hz. What length of wire will produce the sound of frequency 1024 Hz under the same tension?18 cm   20 cm 15 cm   10 cm

Solution

## The correct option is B 20 cm Let initial frequency,f1=256 Hz       Final frequency, f2=1024 Hz       Initial length of the wire, l1=80 cm       Final length of the wire, l2=? The frequency of sound produced by a stretched wire under same tension F∝1l or, fl = constant ∴f1l1=f2l2 or, l2=f1×l1f2=256×801024=20 cm

Suggest corrections