A student designs an experiment to investigate how the resistivity of a metal wire varies with temperature by heating a coil of the wire in a water bath and measuring its resistance.
Which of the following experimental actions is performed specifically to ensure the validity of the investigation?
Repeating the resistance measurements at each temperature and calculating a mean
Measuring the wire's diameter with a micrometer at several different positions and orientations
Keeping the current in the coil extremely low to prevent self-heating of the wire
Calibrating the digital temperature sensor using an ice-point bath before starting
689 exam-style questions on AQA A Level Psychology Scientific processes. Each one has a worked solution and a mark scheme showing where the marks go.