MHTCET 2016 Physics Solved Paper

(a) The fundamental frequency of vibrating wire is given by
fI=

1

2

√

T

µ

Here, µ = mass of string per unit length.
T = tension in the wire
Let x be the frequency of tunning for k according to question
(x -f) = ± 6
∴ f1=

1

2L

√

225

µ

and f2=

1

2L

√

256

µ

∴

f1

f2

=

15

16

⇒ f2=

16

15

×f1
⇒ f2=

16

15

(6+x)
Equating the two cases of f1 we have
(x+ 6) =

16

15

( x - 6)
∴ 15x + 90 = 16x - 96
∴ x = 186Hz