An electrical safety inspector is examining a communal shower facility at a sports center. The shower room has a very hot and humid atmosphere with significant steam.
The inspector recommends that standard household rocker switches on the walls inside the shower room are replaced.
Explain why using a standard household switch in this wet and humid environment poses a major safety hazard.
Suggest a safe method or alternative design for switching the lights in the shower room on and off.
Fine sugar is transported pneumatically (blown by air) through an insulating plastic tube into a metal storage bin inside a food processing factory.
Suggest how the flow of sugar particles through the tube can lead to a large build-up of electrostatic charge on the metal bin.
On a highly humid day, a thin film of moisture forms on the surfaces of the equipment. Explain why there is no large build-up of static charge in this case.
145 exam-style questions on CIE IGCSE Physics 4.2.1a Positive and negative charge. Each one has a worked solution and a mark scheme showing where the marks go.