Final answer:
The cold setting on a blow dryer allows compressed air to expand, cooling as it exits the nozzle due to the energy required for molecular separation. This is not to be confused with the electrical 'cold current', which refers to the initial higher current when devices are switched on, dropping to a steady-state as they warm up.
Step-by-step explanation:
The cold setting on a blow dryer works on the principle of thermodynamics, where the compressed air inside the blow dryer is allowed to expand when it exits the nozzle. This expansion leads to a cooling effect because the air molecules need energy to separate, which they absorb from the surrounding environment, causing the temperature to drop. Reference to the cold current in an electric circuit suggests a current that is higher initially as a device turns on and subsequently drops to a steady-state value as the device, such as a blow dryer, warms up.
Most fuses and circuit breakers are designed to handle this initial surge in current, albeit briefly, allowing devices that draw a high starting current, like motors, to operate without tripping the electrical safety mechanisms. Some devices require special fuses designed to handle sustained high currents. In the context of a blow dryer, the cold setting does not imply an electrical characteristic but rather the physical effect of cold air being produced for styling purposes.