Three identical resistors, each of resistance 4 Ω, are connected in series with a battery. An ammeter in the circuit reads 0.50 A.
(i) Calculate the emf of the battery when three 4 Ω resistors in series draw a current of 0.50 A.
(ii) Determine the new current when one 4 Ω resistor is replaced by an 8 Ω resistor.
(iii) Find the percentage change in current resulting from the replacement.