Why Parallel Resistance Decreases

Part of Series & Parallel Circuits · Section 5 of 16

Deep DiveUnit: ElectricityGCSE

This deep dive covers Why Parallel Resistance Decreases within Series & Parallel Circuits for GCSE Physics. Revise Series & Parallel Circuits in Electricity for GCSE Physics with 20 exam-style questions and 30 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 5 of 16 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.

🔬 Why Parallel Resistance Decreases

🚗 The Motorway Analogy

Imagine traffic flowing to a city. One road (series) creates a bottleneck — all cars must use the same route.

Add a second road (parallel) and traffic flows more easily — cars can choose either route. The "resistance" to traffic flow DECREASES even though you've added more road.

Electricity works the same way. More parallel paths = more routes for electrons = less overall resistance.

Practice questions for Series & Parallel Circuits

In a series circuit, what is true about the current at all points?

  • A. The current is the same at all points
  • B. The current decreases after each component
  • C. The current is largest near the positive terminal
  • D. The current splits at each component
1 markfoundation

A student adds an extra lamp to a parallel circuit. Explain how this affects the total current from the supply and the brightness of the original lamps.

2 marksstandard

Quick recall flashcards

Current in series circuits?
SAME everywhere (I₁ = I₂ = I₃) — only one path for current
Voltage in series circuits?
ADD UP to equal supply voltage (V_supply = V₁ + V₂ + V₃)

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