Final answer:
In a series circuit, all components have the same current flow, but the voltage drop across each varies based on the component's resistance. Kirchhoff's laws, including the junction rule, reinforce that in a series circuit the current is consistent throughout.
Step-by-step explanation:
In a series circuit, several characteristics hold true. For one, each component, be it a resistor or otherwise, experiences the same current flow as there is only one path for the current to take. This is one of the key principles in series circuits. However, the voltage drop across each component is not the same; it varies depending on the resistance of each component. The sum of these voltage drops equals the total voltage supplied by the voltage source.
Furthermore, when utilizing Kirchhoff's laws, specifically the junction rule, also known as the conservation of electric charge, we understand that the total current entering a junction must be equal to the total current leaving the junction. In the context of a series circuit with only one path for the current, this principle essentially confirms that the current is uniform throughout.
To address the specific part of the question regarding the currents in branches, Kirchhoff's junction rule indicates that Ia = I₁ + Ic must be true for any set of branches around a junction. Therefore, if the current in the branch with the voltage source is upward and the currents in the other two branches are downward, the statement given by the rule would indeed be correct.