To convert heat energy into electrical energy efficiently, a material needs to have specific properties:
- Low thermal conductivity: This ensures that heat is retained in the material and does not dissipate too quickly, which is essential for converting heat energy into electrical energy.
- High electrical conductivity: This allows for efficient conduction of the electricity generated from the heat.
When the temperature difference across the material is used for energy conversion (such as in thermoelectric materials), the Seebeck effect occurs. In this process, a temperature difference across the material results in the generation of an electric voltage. To maximize this effect, the material should have low thermal conductivity (to trap the heat) and high electrical conductivity (to conduct the generated electricity).
Therefore, the correct answer is (3) low thermal conductivity and high electrical conductivity.
LIST I | LIST II |
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A. \( \Delta H = -ve, \Delta S = -ve, \Delta G = -ve \) | I. Reaction will be non-spontaneous at high temperature |
B. \( \Delta H = -ve, \Delta S = -ve, \Delta G = +ve \) | II. Reaction will be non-spontaneous at low temperature |
C. \( \Delta H = +ve, \Delta S = +ve, \Delta G = +ve \) | III. Reaction will be spontaneous at low temperature |
D. \( \Delta H = +ve, \Delta S = +ve, \Delta G = -ve \) | IV. Reaction will be spontaneous at high temperature |