Which of the following configurations is NOT possible in a parallel circuit?

The configuration that is not possible in a parallel circuit is when a capacitor is placed in series with a resistor. In a parallel circuit, components are connected across the same two points, meaning they share the same voltage across them. Each component operates independently of the others, allowing for the possibility that some components can function even if others fail.

When a capacitor is placed in series with a resistor, they share the current flowing through them, and the voltage across each depends on their resistance and load characteristics. While this series combination is valid in its own context, it does not fit the definition of components arranged in parallel, where each component must connect across the same two nodes.

The other configurations mentioned, such as two resistors, a single switch, and multiple light bulbs connected in parallel, all represent valid parallel arrangements. In these cases, each component maintains the same voltage, and the overall circuit can operate with independent pathways for current flow, further illustrating their validity within a parallel configuration.