TOKYO - Japan will start dropping water from the air on the No.2 reactor of its quake-stricken nuclear power plant on Friday, the country's nuclear safety agency said on Thursday night.In a separate statement, the Fukushima Daiichi plant's owner, Tokyo Electric Power Co , said white smoke or steam had been seen coming from the No.2 reactor.Thursday's water-bombing efforts had focused on the No.3 reactor.