Explore the idea
Internal resistance
Explore internal resistance within electrical circuits. Use conservation of charge at junctions and conservation of energy around loops. Real sources have internal resistance, so terminal voltage can change with current.
Specification outcomes (4)
- 4.3.2(a) Define source of e.m.f. and internal resistance.
- 4.3.2(b) Define terminal potential difference and 'lost volts'.
- 4.3.2(c)(i) Use and apply E = I(R + r) and E = V + Ir for internal resistance.
- 4.3.2(c)(ii) Use techniques and procedures to determine the internal resistance of a cell or power supply.
H156 v2.0 · May 2026
See it in an exam
No exam example linked yet. You can still explore the explanation and related topics.
PhysicsUK practice
No PhysicsUK question linked yet. New eligible questions appear here as the bank grows.