Which circuit represents a series combination of resistors?
i)
ii)
i) only
In figure i), the resistors are connected end to end. If we observe carefully, the current has to pass through both the resistors in the circuit and there is no other path for the current to take. This is shown in the figure below.
The path depicted in the colour red is the only available path for the current. Such a connection is referred to as a series connection.
In figure ii), the resistors are connected across the battery terminals using separate wires. Now, the current has two separate paths which it could take. Such a connection is referred to as a parallel connection.
As we see, the current has two options regarding the path it could take. It can either take the path depicted in red or the path depicted in blue. The resistors are connected across the same potential difference. Such a connection is called a parallel connection.