Question

In a resonance tube, first and second resonance positions occur respectively at 28 cm and 88 cm. If the frequency of the fork is 300 Hz, then the speed of sound is ____________.

Options

• 300 m/s

• 360 m/s

• 696 m/s

• 480 m/s

Answer 1

In a resonance tube, first and second resonance positions occur respectively at 28 cm and 88 cm. If the frequency of the fork is 300 Hz, then the speed of sound is 360 m/s.

Explanation:

`"for"  1^"st" "resonance"  "L"_1 + "e" = lambda/4`

(e is the end correction)

`"for"  2^"nd" "resonance"  "L"_2 + "e" = (3lambda)/4`

`therefore ("L"_2 - "L"_1) = lambda/2`    ....(i)

`"Speed of sound, v" = "n"lambda`    .....(ii)

∴ From (i) and (ii),

`"v" = "n"  2 ("L"_2 - "L"_1)`

`= 300 xx 2 xx (88 - 28) xx 10^-2`

`= 360  "m/s"`