An external resistor is connected to a battery with a variable emf but constant internal resistance of 0.200 Ω. At an emf of 3.00 V, the resistor draws a current of 0.500 A, and at 6.00 V, the resistor draws a current of 1.50 A.
(a) Is the external resistor ohmic? Prove your answer.
(b) Determine the value of the external resistance under the two different conditions.
(c) In both cases, determine the ratio of Joule heating rates in the external resistor to that in the battery.