Question

The fundamental frequency of a closed pipe is 400 Hz. If `1/3`rd pipe !s tilled with water, then the 3 frequency of 2nd harmonic of the pipe will be (neglect and correction).

पर्याय

• 1200 Hz

• 1800 Hz

• 600 Hz

• 300 Hz

Answer 1

1800 Hz

Explanation:

Fundamental frequency of closed pipe,

n = `"V"/"4L"` = 400

v = 400 × 4L

If `1/3`rd of pipe is filled with water, then remaining length of air column is L - `"L"/3 = "2L"/3`.

Now, fundamental frequency = `"v"/(4((2"L")/3)) = "3v"/"8L"`

The second harmonic of the pipe = 3 × fundamental frequency

`= 3 xx ("3v"/"8L")`

`= 3 xx (3 xx 400 xx "4L")/"8L"`

= 1800 Hz