The sound you typically hear when an oven is pre-heated is a "ding" or a "beep" sound. Most modern ovens are equipped with a timer and temperature indicator, and they emit a specific audible alert to signal that the oven has reached the desired pre-set temperature.
The purpose of this sound is to let the user know that the oven is ready for use and has reached the temperature needed for cooking or baking. It helps ensure that the oven has fully preheated to the desired temperature, allowing the user to place their food inside for proper cooking or baking results. The sound is often distinctive and recognizable, making it easy for users to know when their oven is ready without having to constantly check the display panel.