A single-loop circuit contains two ideal batteries and one resistor connected in series. Battery 1 has an emf of 9.0V with its positive terminal oriented clockwise. Battery 2 has an unknown emf ϵ and is oriented so that its positive terminal is encountered after its negative terminal when moving clockwise. A 150Ω resistor is connected between the two batteries. A student measures the current in the loop to be 30mA clockwise.
Answer the following questions about the circuit.
(1) Part 1: Calculate the potential difference across the resistor, including its sign, based on the measured current and the given resistance.
(2) Part 2: Determine the numerical value of the unknown emf ϵ.
(3) Part 3: State which terminal (positive or negative) of Battery 2 is at the higher electric potential, given the measured current direction, and justify your answer.
(4) Part 4: Compute the power delivered by each battery and the power dissipated in the resistor. Comment on whether energy is conserved within the loop, citing your numerical results.