The successive resonance frequencies in an open organ pipe are 1944 Hz and 2600 Hz. The length of the pipe if the speed of sound in air is 328 m/sec is

Question

$\begin {array} {1 1} (1)\;0.40\: m & \quad (2)\;0.04\: m \\ (3)\;0.50\: m & \quad (4)\;0.25\: m \end {array}$