>
Home · IGCSE 0625 · Electricity and magnetism · Electric current · Practice
Core · Practice questions · Electric current

Flow, direction, and kind.

Six original Cambridge-style questions on electric current: what current is and how it is measured, conventional current versus electron flow, and the difference between direct and alternating current.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.
The facts that earn the marks

Charge flowing, measured in series.

01
Recall
[2 marks]

State what is meant by an electric current, and name the unit in which it is measured.

  • An electric current is a flow of electric charge. ✓
  • It is measured in amperes (A). ✓
02
Recall
[2 marks]

A student wants to measure the current through a lamp.

(a) Name the instrument used.
(b) State how it must be connected in the circuit.

(a) An ammeter. ✓

(b) In series with the lamp (in the same line as the current). ✓

03
Analysis
[2 marks]

In a metal wire, the conventional current flows from X to Y. State the direction in which the electrons flow, and explain why this is different from the conventional current.

  • The electrons flow from Y to X. ✓
  • Electrons are negative and flow from negative to positive, which is opposite to the agreed conventional direction (positive to negative). ✓
04
Recall
[2 marks]

State the difference between direct current and alternating current, and give one source of each.

  • Direct current flows in one direction only; a source is a cell or battery. ✓
  • Alternating current repeatedly reverses direction; a source is the mains supply. ✓
05
Analysis
[2 marks]

Two current-time graphs are recorded. Graph 1 is a horizontal straight line above the time axis. Graph 2 is a wave that rises above the axis and drops below it, again and again. State which graph shows alternating current, and give your reason.

  • Graph 2 shows alternating current. ✓
  • It goes below the axis as well as above, which means the current reverses direction; Graph 1 stays one side, so it is direct current. ✓
06
Analysis
[2 marks]

A student writes, "An ammeter should be connected across a lamp, like a voltmeter, to measure the current." Identify the error and give the correct instruction.

  • An ammeter is not connected across a component. ✓
  • It must be connected in series, in the same line as the lamp, so the current passes through it. ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.