Answer
See answers.
Work Step by Step
a. stays the same. The potential difference is the emf of the ideal battery, which doesn’t change if the current changes.
b. increases. Increasing R7 will decrease the current in the overall circuit and decrease the current supplied by the real battery. There is less of a voltage drop across the internal resistance, and the terminal voltage rises to become closer to the emf.
c. decreases. Increasing R7 will decrease the current in the overall circuit, and the current through R4. V = IR, so the voltage across R4 decreases.
d. increases. If R2 decreases, the parallel combination of R2 and R3 decreases in resistance, so more current flows through the overall circuit, and through R1. V = IR, so the voltage across R1 increases.
e. increases. If R2 decreases, the parallel combination of R2 and R3 decreases in resistance, so more current flows through the overall circuit, through the combination of R4, R5 and R6, and so, through R6.
f. decreases. If R2 decreases, it looks more attractive to current, relative to R3. Current seeks the path of lower resistance, and less current flows through R3.
g. decreases. If R5 increases, the parallel combination of R4, R5 and R6 increases in resistance, so less current flows through the overall circuit, and through R2. V = IR, so the voltage across R2 decreases.
h. increases. If R5 increases, it looks less attractive to current, relative to R4 and R6. Current seeks the path of lower resistance, and more current flows through R4. V = IR, so the voltage across R4 increases.
i. stays the same. The emf of the ideal battery doesn’t change even if the current changes.
