Why do you have to use lemons and not some other fruit on a lemon battery?

Lemons are commonly used in lemon batteries because they contain a high concentration of citric acid, which acts as an electrolyte. This acidic environment facilitates the flow of electric current between the electrodes made of different metals, typically zinc and copper. While other fruits can also be used, lemons are particularly effective due to their acidity and availability, making them a popular choice for simple experiments.