(a.) Find the ratio of the fundamental frequency of sound (a) Open-open and closed-closed pipe having an equal length. (b) Open-Open having length double than closed - closed (b.) The speed of sound in room temperature ( 200 C) air is 343 m/s; in room temperature helium, it is 1010 m/s. The fundamental frequency of an open-closed tube is 315 Hz when the tube is filled with air. What is the fundamental frequency if the air is replaced with helium.