question_answer

The length of a sonometer wire AB is 110 cm. At what distance the two bridge are placed so that the wire is divided into such three parts. Basic frequencies of which are in the ratio of 1 : 2 : 3.

A)  60 cm and 30 cm

B)  60 cm and 90 cm

C)  20 cm and 40 cm

D)  40 cm and 60 cm

Correct Answer: B

Solution :

 \[\because \] \[n\propto \frac{1}{l}\] \[\therefore \] \[AP:PQ:QB=\frac{1}{1}:\frac{1}{2}:\frac{1}{3}\] \[=6:3:2\] \[AP=\frac{6}{6+3+2}\times 110=60\,cm\] \[PQ=\frac{3}{6+3+2}\times 110=30\,cm\] \[\therefore \] \[AQ=90cm\]