Conductors and insulators, current as a flow of charge, conventional current and electron flow, Q = It, direct and alternating current, and reading voltage–time graphs.
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.
Current is not “used up” in a lamp. The same number of electrons that go in come out; what changes is their energy.
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.
Allows charge to flow easily (metals, graphite, salt solutions).
Does not conduct (plastic, rubber, glass).
Rate of flow of charge; ampere (A).
Current is a flow of free electrons.
Conventional current + → −; electron flow − → +.
Charge (C) = current (A) × time (s).
d.c. one direction (flat V–t graph); a.c. reverses (sine wave).
f = 1 ÷ T.
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 (13 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [13 marks]
A lamp is connected to a battery. The current is 0.50 A for 4.0 minutes.
(a) (a) Define electric current. [1]
(b) (b) Calculate the charge that passes through the lamp. [3]
(c) (c) State the direction of the electron flow compared with the conventional current. [2]
(d) (d) Explain the meaning of alternating current. [2]
(e) (e) An a.c. voltage–time graph shows one complete cycle in 0.020 s with a peak of 120 V. Calculate the frequency. [3]
(f) (f) State one difference between the V–t graphs of a battery and the mains supply. [1]
(g) (g) State why mains electricity is supplied as alternating current. [1]
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.