Question

What do you mean by 1 mm rain ??¿¿

Answer 1

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$\rightarrow$ 1 mm rain means, if we do not let the rain water to percolate, run off or even evaporate and if this water is spread on the flat surface uniformly, the height of this rainwater is 1 mm .

Answer 2

Answer:

So 1 mm of rain translates to 1 litre of water in a single metre square. So 802 mm of rain would mean that a single metre square would receive 802 litres of rain, 140 mm would mean 140 litres of water received in a single metre square, and so on.