MHT CET 2017 Physics Solved Paper

(c) For open pipe first overtone, v1=

V

L

For closed pipe first overtone, v2=

3V

4L

∴ v1−v2=

V

L

−

3V

4L

=3
or,

V

4L

=3 ∴

V

L

=12
When length of open pipe is made

L

3

Fundamental frequencyv=

V

2( L 3 )

=

3V

2L

When length of closed pipe is made 3 times,
Fundamental frequency v′ =

V

4(3L)

=

V

12L

Beats produced = v−v′
=

3V

2L

−

V

12L

=

17

12

V

L

[∵

V

L

=12]
=

17

12

×12=17