Question

An air column, closed at one end and open at the other resonates with a tuning fork of frequency v, when its length is 45 cm, 99 cm and at two other lengths in between these values. The wavelength of sound in air column is ____________.

Options

• 180 cm

• 108 cm

• 54 cm

• 36 cm

Answer 1

An air column, closed at one end and open at the other resonates with a tuning fork of frequency v, when its length is 45 cm, 99 cm and at two other lengths in between these values. The wavelength of sound in air column is 36 cm.

Explanation:

`l = 45 = 5 xx 9`

`l' = 99 = 11 xx 9`

So other lengths between these values are,

`l_1 = 7 xx 9 = 63  "cm"`

`l_2 = 9 xx 9 = 81  "cm"`

So fundamental length is 9 cm

`therefore 9 = lambda/4`

`therefore lambda = 9 xx 4 = 36 "cm"`