PHYSICS CONNECTION
Current connects microscopic drift with charge transfer
Current can be found by counting charge per second or by considering how carriers drift through a conductor. These are two descriptions of the same charge flow.
I = ΔQ/Δt = nAev
Follow the reasoning
- Identify charge per carrier and carrier number density.
- Use the cross-sectional area through which the current flows.
- Relate the carrier drift to the macroscopic current.
OFFICIAL OCR QUESTIONS
Try it in a past paper 2
Open the question, then use its mark scheme to check your work.
Question 3(a)
Compare the direction and speed of charge carriers moving through filter paper.
Question 7
Connect a resistor network to internal resistance, drift speed, charge and dissipated energy.
A curated collection checked against the question papers and mark schemes; not a complete past-paper catalogue. Links open official OCR PDFs in a new tab.
ORIGINAL PHYSICSUK QUESTIONS
Put the ideas to work
More practice is on its way
No PhysicsUK question linked yet. New eligible questions appear here as the bank grows.
Specification outcomes (5)
- 4.1.1(a) Define electric current as the rate of flow of charge, I = ΔQ / Δt.
- 4.1.1(c) Know that the elementary charge e equals 1.6 × 10⁻¹⁹ C and that electrons and protons carry charges −e and +e respectively.
- 4.1.1(e) Understand current as the movement of electrons in metals and movement of ions in electrolytes.
- 4.1.2(a) Define and understand mean drift velocity of charge carriers.
- 4.1.2(b) Use and apply I = A n e v, where n is the number density of charge carriers.