Question

if a battery is packed in a box and if only two wires from two terminals are given out how can we decide the positive and the negative terminal of the battery?

Answer 1

keep the two terminals in a potato after some time some Mark is found so we can say that the place where mark I around it is called as positive terminal

Answer 2

place the two terminals of the battery in soft and clean potato. After some time you will observe a mark on one terminal.... that will be the positive terminal