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.
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,


What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)