The concept of resistance, R = V/I, Ohm’s law, the I–V graphs of a metallic conductor, filament lamp and diode, and why ammeters need low resistance and voltmeters high resistance.
5 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
A thick copper cable carries the current to your stove; a thin filament glows white-hot. The difference is resistance.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Copy these into your notebook in your own words — that is how they stick.
Opposition to current; R = V/I; ohm (Ω).
I ∝ V for a metallic conductor at constant temperature.
Straight line through the origin (I against V).
Curved graph; resistance increases as it gets hotter.
Conducts forward above ≈ 0.7 V; blocks in reverse.
In series; very low resistance.
In parallel; very high resistance.
Increases with length and temperature; decreases with cross-sectional area.
3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness. More games in the Physics Arcade.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.
Write full answers, then reveal the mark scheme and tick the points you earned (15 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [15 marks]
A student investigates the current I through a resistor for different p.d. V. The readings are: V = 1.0, 2.0, 3.0, 4.0, 5.0 V; I = 0.10, 0.20, 0.30, 0.40, 0.50 A.
(a) (a) State Ohm’s law. [2]
(b) (b) Describe the graph of I against V and state what it shows. [2]
(c) (c) Calculate the resistance of the resistor. [3]
(d) (d) Draw the circuit diagram used, showing the ammeter and voltmeter. [3]
(e) (e) Sketch the I–V graph for a filament lamp and explain its shape. [3]
(f) (f) State why a voltmeter should have a very high resistance. [2]
Find these in your own past-paper booklets for extra timed practice. Items above are written in the style of these papers; any adapted from a specific question say so.