A student is investigating the resistance of a fixed resistor. She sets up a circuit containing a battery, a switch, the fixed resistor under test, and a control component (labeled component X).
Describe how an ammeter and a voltmeter should be connected to the circuit to measure the current through and the potential difference (p.d.) across the fixed resistor.
In one trial, when the current through the fixed resistor is 0.45 A, the potential difference across it is 5.4 V. Calculate the resistance of the resistor.
State the name of component X, which is represented by a rectangular resistor icon with a diagonal arrow pointing through it.
Describe and explain how the student uses component X to carry out her investigation of how the resistance changes over a range of currents.
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.