Current, Potential Difference, Power and Resistance
Apply charge, potential difference, resistance, power and circuit rules to components and networks.
How to study Higher Physics
Move between physical models, relationships, units, graphs and justified conclusions, while using current official materials for exact paper and assignment conditions.
Core concepts
Concept 1
charge flow and current
Exam cue: Mark junction currents and component potential differences.
Concept 2
Ohm’s law and component behaviour
Exam cue: Reduce networks systematically before finding branch values.
Concept 3
series and parallel circuit rules
Exam cue: Use the loaded circuit, not an isolated formula, for potential dividers.
Concept 4
power, energy and potential dividers
Risk pitfalls and guardrails
Adding parallel resistances directly.
Guardrail: Check assumptions, prefixes, units, significant figures and whether the statement is supported by evidence.
Assuming every component has constant resistance.
Guardrail: Check assumptions, prefixes, units, significant figures and whether the statement is supported by evidence.
Confusing electrical power with energy.
Guardrail: Check assumptions, prefixes, units, significant figures and whether the statement is supported by evidence.
Memory anchors
Current
I = Q/t.
Potential difference
V = E/Q, energy transferred per unit charge.
Resistance
R = V/I.
Series rule
Current is common; potential differences add.
Parallel rule
Potential difference is common; branch currents add.
Electrical power
P = IV, with equivalent forms from V = IR.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
A 12 Ω resistor carries 0.50 A. What potential difference is across it?
A component has 9.0 V across it and current 0.30 A. Find resistance.
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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