Two batteries of different emf’s and internal resistances are connected in series with each other and with an external load resistor. The current is 3 ampere. When the polarity of one battery is reversed the current becomes 1 ampere. The ratio of e.m.f’s of two batteries is
(1) 3.0
(2) 2.5
(3) 2.0
(4) 1.5
