A 12.0 V storage battery is connected to three resistors, 4.75, 14.0 and 21.0, respectively. The resistors are joined in series.

(a)Calculate the equivalent resistance.
(b)What is the current in the circuit?
Answer in units of A.

(a).  The equivalent resistance of a series circuit is the SUM of the individual resistances in the circuit.

(4.75Ω + 15Ω + 21Ω )  =  39.75Ω

(b). Current = (voltage) / (resistance)

Current = (12 v) / (39.75Ω)

Current = 0.302 Amperes (rounded to the nearest MilliAmpere))

conservation of mass

mass before something happens = mass afterwards