What is 20th law of cricket?

Answer 1

Law 20 of the Laws of Cricket concern what happens if the ball should somehow be lost or made unrecoverable (unassisted) in the course of play. It specifies that should this happen, the fielding team can call "lost ball", which renders the ball dead and the play over. The batting team is allowed to keep any penalty runs and is given credit for a six (if they've managed to score more than a six in the course of the play, those runs are kept instead). A replacement ball is then brought in which is in similar condition to the one that was lost.