This deep dive covers Ohmic vs Non-Ohmic Conductors within Resistance & Ohm's Law for GCSE Physics. Revise Resistance & Ohm's Law in Electricity for GCSE Physics with 16 exam-style questions and 30 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. 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.
⚡ Ohmic vs Non-Ohmic Conductors
Ohmic conductors: Resistance stays CONSTANT
- Examples: Fixed resistors, metal wires (at constant temperature)
- V-I graph is a straight line through the origin
- Obey Ohm's Law: V = IR with constant R
Non-ohmic components: Resistance CHANGES
- Filament lamp — R increases as it heats up (curved V-I graph)
- Diode — very high R in one direction, low R in the other (only allows current one way)
- Thermistor — R decreases as temperature increases
- LDR (light-dependent resistor) — R decreases as light intensity increases
Practice questions for Resistance & Ohm's Law
Which of the following best describes electrical resistance?
Explain what is meant by an ohmic conductor.
Quick recall flashcards
Ohm's Law equation?
V = IR where V = voltage (V), I = current (A), R = resistance (Ω)
Unit of resistance?
Ohm (Ω)