Concepts of Physics

IIT JEE Physics (1978-2018: 41 Years) Topic-wise Complete Solutions

Thermal Conductivity of Various Materials

Introduction

We make use of conductors and insulators of heat in daily life. Different conductors have different thermal conductivity.

Apparatus

three similar wires (about 20 cm long and 2 cm thick) of copper, aluminium, and iron, a candle

Procedure

Tie one end of each wire together. Heat the junction of the wires with a lighted candle. After half a minute or so, touch the ends of the wires and try to observe which one is heated most.

Discussion

Copper wire will be heated most and the iron wire the least as thermal conductivity of copper is more than that of aluminium and thermal conductivity of iron is less than that of aluminium. The thermal conductivity depends on molecular structure of these materials.