Why is the current flow greater in a parallel circuit than it is in a series circuit?
For a potential difference V across a resistor R, the current I that flows through the resistor is given by Ohm's law as I = V/R
As current is inversely proportional to resistance, for the same potential difference if the resistance is higher, the current flowing through the resistor is lower. And if the resistance remains the same, for a higher potential difference across the resistor a higher current flows though it.
In a parallel circuit, the potential difference across each of the resistors that make up the circuit is the same. This leads to a higher current flowing through each resistor and subsequently the total current flowing through all the resistors is higher. In a series ciruit on the other hand, the potential difference applied across all the resistors that make up the circuit is divided into smaller fractions across each of the resistors. This leads to a smaller current flowing through each of the resistors and subsequently a smaller total current flowing through the circuit.
The current flow = Voltage/Resistance or current is inversely proportional to resistance. More the resistance, lesser the current and vice versa.
Consider there are two resistive loads of equal magnitude R which are subjected to the same voltage V in series and in parallel turn by turn.
if load is applied in series then the combined resistance will be 2R and the current flowing through the circuit will be V/2R.
Now if the load is applied in parallel then the current passing through each circuit will be equal to R/V.
It can be seen that the current passing in the parallel circuits V/R is double the current passing through the circuit in series which is V/2R.
Hence it can be inferred that the current passing in the parallel circuit is greater than the current passing through the series circuit.
I hope this example clarifies the question.