New Delhi, Oct 13 (UNI) As polling began for the first phase of the Bihar assembly elections, Prime Minister Narendra Modi has encouraged voters, particularly first timers to cast their votes. 'Urging all those voting today in Bihar to vote in large numbers. I particularly urge my young friends to cast their vote,' he tweeted on the occasion. Till 0900 hrs, about 13 per cent ballots were exercised within two hours of start of polling in 49 constituencies where voting was being held. UNI SD SHS SB 1110