An electric current is established in a copper wire when it is connected to a battery. Which of the following statements about the charge carriers responsible for this current is correct?
The current is caused by the flow of positively charged protons.
The current is caused by the flow of negatively charged electrons.
The current is caused by the flow of neutral neutrons.
The current is caused by the flow of both positive protons and negative electrons in opposite directions.
452 exam-style questions on CIE IGCSE Physics 4.2 Electrical quantities, covering 4.2.1a Positive and negative charge, 4.2.1b Charging by friction and detecting charge, 4.2.1c Electrical conductors and insulators, 4.2.1d Electric fields and electric field patterns, 4.2.2a Electric current, charge and measuring current, 4.2.2b Conduction in metals and the direction of current, 4.2.2c Direct current and alternating current, 4.2.3a Electromotive force, 4.2.3b Potential difference and voltmeters, 4.2.4a Resistance, 4.2.4b Resistance of a metallic wire, 4.2.4c Current–voltage graphs, and 4.2.5 Electrical energy and electrical power. Each one has a worked solution and a mark scheme showing where the marks go.