Question

Thermal conductivity is maximum for which substance?
A. Ice
B. Silver
C. Wood

Answer 1

The capacity of a substance to conduct heat is measured by its thermal conductivity. Low thermal conductivity materials transmit heat at a slower pace than high thermal conductivity materials. Metals, for example, have a high thermal conductivity and are extremely effective at transferring heat, whereas insulating materials like Styrofoam are the polar opposite. High thermal conductivity materials are commonly utilised in heat sink applications, while low thermal conductivity materials are used as thermal insulation.

Complete answer:
The thermal conductivities of typical materials range from four to eight orders of magnitude. Pure metals have a high thermal conductivity, whereas gases have a low thermal conductivity. Copper, for example, has a heat conductivity of 10000 times that of air under normal circumstances.

Allotropes of carbon, such as graphite and diamond, are thought to have the greatest thermal conductivities at room temperature of any material. Natural diamond has a thermal conductivity many times that of a highly conductive metal like copper at ambient temperature (although the precise value varies depending on the diamond type).Thermal conductivity for metal is high hence silver is the correct answer.

Hence, the correct answer is option B.

Additional information:
According to the Wiedemann–Franz equation, thermal conductivity in metals closely parallels electrical conductivity, as freely moving valence electrons transmit not just electric current but also heat energy. Due to the increasing relevance of phonon carriers for heat in non-metals, the typical connection between electrical and thermal conductance does not hold for other materials. Silver is more electrically conductive than diamond, which is an electrical insulator yet transmits heat via phonons owing to its ordered atom arrangement.

Note: Non-metal thermal conductivities are primarily due to lattice vibrations. The mean free route of the phonons does not fluctuate considerably when temperatures are high, suggesting that the thermal conductivity of non-metals does not alter much. When the conductivity and heat capacity of a non-heat metal are lowered to temperatures below the Debye temperature, the conductivity and heat capacity of the non-heat metal both decrease.