GCSE Physics: Electric Circuits

Electricity is one of the most calculation-dense topics in GCSE Physics, and this quiz covers its foundation layer: charge, current, potential difference and resistance, and how they connect.

The calculation questions work all three of the core relationships with concrete values. Charge flow from current and time — including the classic trap of a time given in minutes that must become seconds before multiplying. Potential difference as energy per unit charge, with a battery transferring 40 J to move 5 C. And V = IR in all three arrangements: finding resistance from voltage and current, voltage from current and resistance, and current from voltage and resistance. In line with the real exams, where an equations sheet is provided, none of these questions ask you to recall the equation — they test whether you can select it, rearrange it and substitute correctly.

The physical-reasoning questions cover what the specification calls the factors affecting resistance: why a longer wire has more resistance and a thicker wire less, framed as statement-selection so the misconceptions (confusing length and area effects) are directly confronted. The two special components get realistic scenario questions: a light-dependent resistor in a room where a lamp is switched on — resistance falls, so current rises at constant voltage — and a thermistor in a heating control system, where falling resistance with rising temperature is what makes the sensing application work.

Every question is fully self-contained with numbers and units in the text, and each explanation shows the substitution and rearrangement explicitly. This set is the natural preparation for the Series and Parallel Circuits quiz in the same collection, which builds circuit-level rules on top of these component-level foundations.

• Calculate charge flow from current and time with correct unit conversion
• Interpret potential difference as energy transferred per unit charge
• Apply V = IR in all three rearrangements with given values
• Explain how length and thickness affect the resistance of a wire
• Predict LDR and thermistor behaviour in realistic sensing scenarios

Topic scope follows the Electricity section of the Department for Education's GCSE combined science and physics subject content: charge and current, potential difference, resistance and the factors affecting it, and the characteristics of LDRs and thermistors. Reflects the equations sheet arrangement — application, not formula recall.