Class 11 NEET Physics Waves Questions Questions

Let L(=100cm) be the length of the wire and L1,L2 and L3 are the lengths of the segments as shown in the figure.Fundamental frequency, v∝

1

L

As the fundamental frequencies are in the ratio of 1: 3: 5 ,
∴L1:L2:L3=

1

1

:

1

3

:

1

5

=15:5:3
Let x be the common factor. Then
15x+5x+3x=L=100
23x=100 or x=

100

23

∴L1=15×

100

23

=

1500

23

cm
L2=5×

100

23

=

500

23

cm; L3=3×

100

23

=

300

23

cm
∴ The bridges should be placed from A at

1500

23

cm and

2000

23

cm respectively.