High School

Two batteries of different EMFs and different internal resistances are connected as shown. The voltage across AB in volts is 6 V.

a) True
b) False

Answer :

Final answer:

The statement that Source A's circuit must have a higher external resistance than Source B's circuit to supply the same current with lower internal resistance is a) true, based on the relationship described by Ohm's Law, V=IR.

Explanation:

True, Considering the scenario where two voltage sources have the same electromotive force (EMF) but different internal resistances, and they supply the same current to their respective circuits, it implies that the total voltage drop across the internal resistance and external load in each circuit must be equal to their EMF. Since the first source (Source A) has a lower internal resistance than the second source (Source B), it means that for both to supply the same current, the external resistance in Source A's circuit must be higher than that in Source B's circuit. The voltage drop across the internal resistance will be less in Source A's circuit than in Source B's circuit, leaving more voltage to be dropped across the external resistance in Source A's circuit.

This can be understood by applying Ohm's Law, V=IR, which states that the voltage drop (V) across a resistor is the product of the current (I) flowing through it and its resistance (R). With the same EMF and current in both circuits, Source A with a lower internal resistance requires a higher external resistance to balance the equation and maintain the same current flow as Source B with a higher internal resistance.