Hi Nilamni,

What exactally you want to know in this?

Regards

As we know, ? = 1 2 L F µ ; w h e r e v i s f r e q u e n c y , F i s t h e t e n s i o n i n t h e s t r i n g a n d µ i s t h e m a s s d e n s i t y o f s t r i n g According to Question, 288 = 1 2 × 80 F µ . . . . . . . . . . . . . . . ( 1 ) 312 = 1 2 L F µ . . . . . . . . . . . . . . . . . . . . ( 2 ) O n d i v i d i n g e q u a t i o n ( 1 ) a n d ( 2 ) w e g e t , 288 312 = 2 L 2 × 80 ? L = 73 . 85 c m