With increase in temperature the thermal conductivity of non-metallic amorphous solids...

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With increase in temperature, the thermal conductivity of non-metallic amorphous solids

A. Decreases

B. Increases

C. Remains constant

D. First decreases upto certain temperature and then increases

Answer: Option B

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Comments (1)

Atanu Chatterjee:

4 months ago

The correct answer is:

A. Decreases

Explanation:
In non-metallic amorphous solids (e.g., glass, polymers):

Heat is conducted mainly through vibrations of atoms (phonons).

Unlike crystalline solids, amorphous solids have disordered atomic structures, which scatter phonons more.

As temperature increases, phonon-phonon interactions and scattering increase further.

This results in a decrease in the mean free path of phonons, thereby reducing thermal conductivity.

This behavior is monotonic—it decreases continuously with temperature, unlike some crystalline materials which may show a peak.

✅ Final Answer: A. Decreases

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