Electroplating metals.
Explanation
Electric current produces three primary effects depending on the nature of the conductor and the apparatus used: the heating effect, the magnetic effect, and the chemical effect. The chemical effect of electric current occurs when current passes through a conducting solution (electrolyte), resulting in a chemical reaction such as the dissociation of ions.Analysis of Options:
- Lighting a bulb. Lighting a bulb: This is an application of the heating effect of electric current. In an incandescent bulb, the filament becomes hot due to resistance and emits light.
- Electroplating metals. Electroplating metals: This is a direct application of the chemical effect of electric current (electrolysis). The process involves depositing a layer of a desired metal onto another material by passing an electric current through a solution containing ions of the metal to be deposited.
- Running a fan. Running a fan: This utilizes the magnetic effect of electric current. An electric motor inside the fan converts electrical energy into mechanical energy through electromagnetic interaction.
- Heating water in a geyser. Heating water in a geyser: This is based on the heating effect (Joule heating), where electrical energy is converted into heat energy as current passes through a high-resistance heating element.
Key Takeaway: The chemical effect of electric current is utilized in processes involving electrolytes, such as electroplating, electro-refining of metals, and the decomposition of chemical compounds.