What is the method of producing electricity by joining two dissimilar metals and applying heat?

• A. Photovoltaic Effect
• B. Thermal Generation
• C. Pyroelectricity
• D. Thermocouple

Answer: (D)

The method of producing electricity by joining two dissimilar metals and applying heat is known as a thermocouple. A thermocouple consists of two different metals that are joined at one end, forming a junction. When this junction is heated, it creates a temperature difference between the hot junction and the cold junction, which generates a voltage due to the thermoelectric effect. This principle is utilized in various applications, including temperature measurement and as a power source in certain sensors.

The other methods listed do not involve the specific combination of dissimilar metals and heat to generate electricity. For example, the photovoltaic effect refers to the generation of electric current in a material upon exposure to light, commonly applied in solar panels. Thermal generation typically describes the process of producing electricity from thermal energy but does not explicitly refer to dissimilar metals. Pyroelectricity involves the generation of electricity from temperature changes in specific materials, but it does not rely solely on the combination of two different metals in the same way thermocouples do.