Total resistance
Add the resistances in the loop to get the equivalent resistance.
AQA 8463 · DC series circuits
Series circuits: the current does not divide
The shared-current mark. In a single loop the current is identical at every point, and the mark is for stating that before any component calculation.
Reviewed family · Studara-authored items · No grade-uplift claim
The lost mark
One answer. Several places the method can fail.
Studara does not reduce the response to right or wrong. The reviewed contract checks these states independently.
Shared current
Use I = V ÷ R with the total, and state that this current is the same everywhere in the loop.
Component potential difference
Apply V = IR to each component using that shared current.
Why it goes wrong
The diagnosis stays uncertainty-safe.
A wrong response can support a specific measured diagnosis. A blind multiple-choice diagnostic records only a possible cause until later working provides stronger evidence.
01
The error
Dividing the current between the components as though the circuit were parallel, usually by splitting it in proportion to resistance.
02
Why it survives revision
Potential difference genuinely does divide across components in series, so half the mental model is correct and keeps being confirmed. The two rules are learned together and it is the pairing, not either rule alone, that gets remembered wrong.
The worked repair
Repair the smallest broken step.
Teaching is not evidence. This one move is the repair; the proof checks begin after it disappears.
State “current is the same at every point in this loop” before calculating anything, then use V = IR per component.
What happens after the repair
Correction is the start, not the result.
Immediate
Asked again straight away, on a different question
The repair leaves the screen and a new authored item checks the method unassisted. Being taught something is never evidence that it was learned, so this is the first stage that counts at all.
Delayed
Asked again after at least 1 day
A parallel form of the same method, unassisted, with the repair no longer on screen. A retest in the same session does not count.
Transfer
Asked again when the surface changes
The transfer form adds a component or asks for the potential difference across one named resistor, so the shared-current fact has to be used rather than recited.
Exam
Asked again under exam conditions
Timed, carrying the mark tariff, in an exam-like response format and aligned to the specification. Any one of those missing and the evidence is refused.
REVIEWED BOUNDARY
This page covers one reviewed family: DC series circuits. Model equivalent resistance, shared current and component potential difference through independently checked working. Other families within the same GCSE Physics topic are outside this reviewed journey, and Studara does not apply the proof label to material that has not been reviewed. No grade-uplift claim is made anywhere on this site.
Straight answers
Before you use this guide.
Does current split in a series circuit?
No. Current is the same at every point in a single loop. It is the potential difference that divides between components.
How do I find the voltage across one resistor?
Find the total resistance, then the shared current, then multiply that current by the individual resistance.
Does Studara guarantee a higher grade?
No. Studara has not run a controlled outcome study and publishes no grade-uplift claim. What has been measured, what is withheld, and the metric that failed its bar are all on the public evidence page.
Turn this method into evidence